TEHRAN AGAIN. Spurred on by ayatollahs declaiming from Shi'ite religious citadels outside Iran's borders, crowds of rioters have disrupted life in the capital, brought the shah's regime to the verge of bankruptcy, and forced him to grant a fully constitutional regime. But the shah is firmly committed to autocracy. He regroups his troops, who attack the majlis, or parliament, while it is in session, arrest some of its leaders and disperse its other members. The Iranian revolution cannot be so easily destroyed. Within a year, two revolutionary columns march on Tehran; one is commanded by tribal leaders and traditionalists, the other by modernizing reformers. They stoem the capital, oust the ruler in favor of his young son and reestablish constitutional rule.Alas, a parliament divided among clerical traditionalists, privileged grandees and liberal modernizers cannot rule effectively. Amid mounting struggle, much of it over the issue of modernization, foreign powers find opportunity for trying to revive their old hegemony. Order can be restored only under autocratic rule, with a strong shah serving as protector of nationism and leader of modernization. A new, vigorous dynasty is founded.

The above is not a think-tank projection from present to future Iran, but a careful summary of some of the vital events in Iranian political history in the first two decades of this century, the period which witnessed the first flowering of the modern Iranian revolution and the rise of the Pahlevi rulers.

Contemporary events in Iran, and the issues of revolution, traditionalism and modernization, cannot be understood fully as the results of recent developments. The opposition of traditional clergy to modernization and the Iranian ruler is as old as this century. So, too, are economic and social dislocations caused by modernization. An unorthodox coalition of clerical traditionalists, grandees, tribal leaders and modernizing liberals against the Iranian potentate is equally hoary. Current Iranian unrest is part of a sporadic but ongoing revolution, which began over seven decades ago. The alignment of forces against royal absolutism is not significantly different than it was at the origins of the revolution. A Series of Convulsions

THE CRITICAL question for comprehending the Iranian revolution, then, is why long-standing political animosities have burst out again, after some decades of smoldering quiescence. If rebellion is not new, to what extent is this 70-year-old revolution reaching its climatic phase? What are the dangers of Iranian revolt for current American interests in the Middle East?

Despite some surface indicators to the contrary, Iran is hardly prone to turn toward Islamic revival, or to embrace communism, or to reject aan alignment with the West-unless Amercian policy blunders make it do so; and there are discernible reasons why dissidence has risen again, reasons rooted considerably in Iran's 20th century experience with the West.

What needs particularly to be understood is that the Iranian revolution is one with other long-ongoing revolutions which affected the great cultures and political societies of Asia and the Near East in the 20th century. These revolutions were offshoots of what may be termed modernization crises, convulsions in the old political orders of Asia which coourred when they began consciously and rapidly to modernize, initially in order to thwart the incursions of western imperialism.

Effective Military modernization eventually required a broad grasp of western science and technology, and hence of western education in general; and modernization also necessitated the centralization of state power (and minimization of the freedom of local entities), modern financial and budgetary systems (and abolition of the tax priviledges of the elites), secularization of law and education (removing these subjects from traditional clerical lawgivers and educators), and increased economic contract with the West (expanding the size and importance of indigenous commercial classes). Western powers extracted free trade, extraterritoriality and other concessions in return for loans to finance modernization.

The result was political tumult, polarization and revolution, as clergy, aristocrats, local potentates and others battled the loss of their privileges or the rise of a Western intellectual orientation, or as westernized merchants, intellectuals and others fought for greater modernization, a constitution and the abolition of the concession granted to western powers. The consequence, often, was multiple or ongoing revolutions which culminated in radical uprisings.

When the modernization crisis led to revolution, for example, in China, it also ruptured the old Chinese social order, destroyed the credibility of the Mandarin elite as guides and protectors, and brought peasant nationalist leaders like Sun Yat-sen and peasant Communist chieftains like Mao Tse-tunf to the fore. Once the old order was fragmented there was no stopping place for Chinese revolution short of communism, partly because of the rigidity and ineptitude of the old elites, and the failure of the nationalist Kuoming-tang party to seize effectively the ferule of modernization. Between Russia and Britain

IN IRAN the old social order has been reformed and partly modernized but never overturned. To a considerable extent this is because the old Iranian elites have been reasonably effective in adopting economic modernization, particularly under the present dynasty, while diving on political liberalism and social reform. The limits of political liberalization, however, the long tolerance of a strong Pahlevi dynasty, and the reemergence of unrest are explained largely by Iran's complex encounter with imperalism.

Iran's primary political problem through the mid-20th century was finding governance that could resist foreign domination. The achievement of liberal constitutional rule was secondary. The two issues always were related, however, and remain so today; and they must be understood in their historical context to interpret their contemporary meaning.

**russia's temporary setback in the Russo-Japanese War, in 1905, and weakness in Asia provided the occasion for the rebellion which wrested a constitution from the Russian-dominated Shah Muhammed Ali Qajar. The shah's subsequent bombardment and dispersal of the majlis was instigated by Russia. Obversely, the Bakhtiari tribe marched north t depose Muhammed Aai in 1909 with the covert encouragment of the British, who wished to counter Russian predominance. Two years later the two great powerts encouraged a conservative purge of the government's liberal nationalist, who had attacked their privileges and those of the Iranian upper classes. The Iranian constitution, then, fell prey to imperialism and conservative Iranian elitism.

The threat of foreign domination and the inability of Iran's corrupt ruling oligarchy to prevent it, or to control the country, account for the advent of the Pahlevi dynasty. After the Bolshevik revolution disrupted Russia, and after World War I, Iranian nationalists justifiably feared that their country would become an informal British colony, squeezed between British possessions and the Persian Gulf, a British lake. They were alarmed particularly by British proposals for a virtual protectorate over Iran. Numbers of Iranian ministers and legislators received British financial "subventions," and the parliamentary regime was divided and impotent.

Thus many dissident nationalists made common cause with the vigorous army leader, Reza Pahlevi, and his quick, decisive coup outsed the venal government. He prevented foreign domination, brought order to the country, and launched effective modernizing policies; and he also toppled the last, figurehead Qajar shah, and established the Pahlevi dynasty. Understandably, he met his eventual demise at the hands of the imperial powers; his close relations with Germany (always a "third force" in Iran), stimulated an Anglo-Russian invasion in 1941 which deposed him in favor of his son, the present ruler. The End of Imperialsim

SHAH MOHAMMED REZA'S destiny has been intertwined equally with imperialism and foreign power, and remains so today. The shah seemed feckless when forced to flee in 1953, at a time that his prime minister, Mohammed Mossadegh, had become locked in struggle with the western powers over oil rights and concessions, and refused to heed the shah's dismissal.

Since that grim episode, the shah has become increasingly forceful as defender of national interests. While remaining a reliable western military ally, he become at times almost bellicose in demanding western economic selfishness, and in propounding Iranian development plans - to be floated on oil price rises inconvenient and expensive for the West.

But the shah's role as a spokesman for OPEC, whose oilcartel putatively is able to humble the West, has had another, deeper significance in Iran. It has signed the demise of the old era of imperialism, in which (even in the present shah's time) western powers embargoed Iran's oil at will, to force conformance with their policies. The threat of imperialism, more than any other, historically justified Pahlevi absolutism. The growth of modernization, technology, displacement, education, wealth, the middle class, leftism and rising expectations all have contributed, no doubt, to the present unrest. But the departure of the British from the Persian Gulf, the demise of the old imperialism, the growth of the Middle East's wealth and influence removed what was the most important Iranian political issue of this century: survival and independence-and moved to primacy for the first time the 70-year-old issue of constitutional, parliamentaty rule.

This change has unleashed the liberalism of liberal nationalists, who in the past had been coopted by Pahlevi nationalism, and now have become foes of Pahlevi authoritarianism. It is focused the attention of the intelligentsia and others on domestic issues, and has given resonance to the cries of the Ayatollah Khomeini for the shah's fall. No Turning Back

HOW WILL all this end? Will the new stimulti to Iranian liberalism and against royal absolutism lead to an Islamic revival in a society which flaunts traditional gard like the chador as defiance of the shah? Or will protracted unrest precipitate a Communist Iran, and should the United States use influence or intervention to prop up the shah, counter Soviet medding and prevent the collapse of American interests in the Middle East?

If the past is prologue, and tells that yes, a shah can be toppled, it also indicates the unlikeliness of the emergence of an Islamic state of Iran, under the guidance of the ayatollahs. Iran will remain secular, modernizing, oil-producing and, except under the worst of Amercian blunders, pro-western. The battle of secularization was fought out decades ago, and lost by the religious and anti-modernizing forces when they were much stronger than now. Most main elements in Iran - middle class, grandees, workers, army - support at least economic modernization.

The pattern of rallying the people in the name of religious revival and tradition is a frequent one in 20th-century Asian revolutions. When a regime begins to seem oppressive, and is a modernizing one, the banners of traditional Islam - or Himduism or Buddhism - have been useful symbols under which to mass support. But when the opportunity has occurred, no nation has turned back to a more traditional past, and Iran has rejected doing so already.

Iran's eastern neighbour, India, was a more genuine candidate for a traditionalist revival, and had the greatest of pseudo-religious, anti-modernizing leaders in the Mahatma Gandhi. Gandhi's anti-modernizing influence was sufficient to make leaders of the National Congress, including such anglicized sophisticates as the Nehrus, do hand-loom spinning every day, as a symbolic and material rejection of western industrialization. Gandhi was immensely valuable in providing a motif and means for rallying the nation against the British raj. Yet when the moment of choice came, when the British were gone, India rejected its spiritual prophets in the name of economic profits, and proceeded as rapidly as possible toward industrialization, scientific mastery and nuclear capability.

The Ayatollah Khomeini can expect no better from his secular followers than was achieved by the Mahatma. Some of his predecessors experienced worse. In the first phase of the Iranian revolution, after Shah Muhammed Ali Qajar was toppled, religious traditionalists and modernizers began to clash seriously in the majlis over secularization of the law, an issue symbolizing the whole question of modernization in the new Iranian state. The struggle resulted in street warfare in Tehran, and the traditionalists were defeated in open batlle and by parliamentary vote.

Since then, the westernized middle class, intelligentsia and other modernizing elements have grown greatly, and at least some of the benefits of modernization have been felt at many levels of society. Not all Iranians favor western social mores, but most have embraced secularization and economic development with vigor. A Hard Land to Communize

WHAT ARE the prospects of the Communists coming to power, perhaps leapfrogging to control with Soviet help after an unholy Islamic-Communist alliance topples the ruler?

Of course the Soviet Union meddles in Iran, using its diplomats and technicians and, occasionally, Armenian and Afghan emigres for covert activities - just as the KGB notoriously coopts Soviet citizens for varieties of spy activities around the world. Of course Iran has its Communist Party. But Iran will be hard to communize.

It is not a society of discontented peasants, radicalized by war, poverty, foreign domination and backwards, venal elites, as were China and Vietnam.It is not overpopulated, flooded with land-hungry masses ripe for the slogans of bread and Marxism. There are no invading armies to provide Iranian Communists with a rationale for organizing guerrilla battalions and for channeling armed nationalism toward Communist objectives. The Iranian army hardly has been radicalized. The new middle class of tobacco traders, auto dealers and others has more at stake in an open economy and prosperity than in parliamentary liberty or the tumult which could encourage communism. Grandees and tribal leaders remain powerful, cautious and resistance to social leveling. Religious leaders sway the masses and social traditionalism poses as revolt.

No wonder an Iranian Mao Tse-tung or Ho Chi Minh has not arisen. When a country has completed the colonialistic phase of modernization without being radicalized it is unlikely to be radicalized soon after. There is a stopping place in Iran between Pahlevi autocracy and communism, and only long frustration of constitutional ambitions can permanently turn the intelligentsia toward leftism. The Case for Restraint

THE SHAH can prove sufficiently inept and rigid to precipitate his own downfall, but this need not occur. Timely concessions, for example, could provide the framework for his exertion of power by influence and patronage politics.

Even if he should tumble, chaos and communism are unlikely to follow. A shakeout period would be necessary for any parliamentary regime, but would not inevitably be much more difficult than it was in India, a somewhat similar, economically westernized, socially conservative society. The shah represents by lineage, moreover, military intervention in politics. If he long proves unable to tamp down unrest, or is ousted in favor of an ultimately chaotic parliamentary regime, there is precedent for army intervention or another lineage.

The United States can only "lose Iran" by most blundering of interventionist policies. Iran remains wary, by long experience, of great powers, and there is much suspicion of the United States. But Iran fears only one country definitively: the Soviet Union.

The great bear to the north has clawed away at Iranian territory, massed armies threateningly, occupied northern Iran, and tried to influence Iranian affairs in Czarist and Communist times alike. A Communist Iran is hardly likely, but a Communist Iran would be less comradely with the Russians than are the Chinese.

American intervention or influence to try to bolster the shah would exemplify an archetypal Cold War mistake: ignoring the sociology of change in a modernizing country. In fact, Iran provides almost a model for benign American restraint and nonintervention: a modernizing, enriching, moderate society, with ample land and resources, a relatively weak Communist movement, and sufficient trepidation about the Soviet Union to make friendship with the United States a virtual necessity - unless we spoil it.

Seventy years ago, the Iranian liberals, trusting the United States as the world's only great, non-colonialist democracy, brought in a former American diplomat named Morgan Shuster to help shape the new Iranian state. His reforms were the primary target of the conservative-imperialist coup of 1909.

Iranian liberalism has had a difficult birth passage. Foreign intervention to preserve the spoils of imperialism pandered to reactionary and corrupt elements in Iranian society, at the expense of many able democrats, condemned to retirement and silence. Eventually foreign foreign intervention caused an alliance with modernizing militarists which liberals found necessary if destructive to their constitutional objectives.

It is barely possible that a brighter moment is ahead for Iranian liberalism. Today, Amercian restraint, just conceiving, might allow the slow emergence of a democracy and help revive an almost forgotten Iranian belief about this country