To watch the Polish crisis is to see how new economic realities have changed politics and handcuffed traditional diplomacy. Almost by default, the West has become a passive spectator. Its considerable economic power is so splintered among different governments and private banks that it is diluted almost to nothingness.

Contrary to conventional wisdom, the West isn't inevitably helpless. Poland faces not only military domination and political dissolution but also economic collapse. And the West might forestall that. An economic rescue, probably costing between $5 billion and $15 billion, would allow the Poles to buy needed imports and a more precious commodity -- time.

To what end? Would such aid subsidize Soviet repression? Or would it maintain Poland's current liberalization? No one can really say. These questions are not only unanswered; they are largely unasked. Democracy, once again, is mired in its own divisions.

After a fashion, Poland is a case of detente working. Beginning in the early 1970s, the government of Edward Gierek embarked on a deliberate policy of promoting trade with the West. Increased trade unintentionally brought political liberalization.

Gierek's idea was to buy popularity with rapid economic growth. To do that, he imported large amounts of Western technology purchased with bank loans from the West -- on the assumption that new factories could pay for themselves by exporting their products to the West. The original loans were in "hard" currencies (such as the dollar or deutsche mark), and so would be the export earnings.

It didn't work out. Economic mismanagement begot an unsustainable growth rate, persistent trade deficits with the West ($1.1 billion in 1979), a staggering debt (now estimated between $23 billion and $27 billion) and deep popular dissatisfaction. Last summer's strikes, which unseated Gierek, started over meat price increases. But economic grievances quickly broadened into political grievances, and the two became inextricably intertwined.

Government specialists and academic experts, such as Tufts University's Sarah Terry, now paint a grim picture of the Polish economy. Consider:

Coal : It's both the chief source of power and the largest export to the West, accounting for about a sixth of the total. But production has declined sharply, from 201 million metric tons in 1979 to an annual rate of only 155 million tons in January. The government's agreement to reduce the miners' workweek from six to five days has cut output, but so have poor mining practices in the past few years.

Food : Port supplies, a lightning rod for consumer dissatisfaction and Poland's second-largest export, have declined 7 percent between 1975 and 1979. Although 70 percent of Poland's farmland is privately held, the farmers are at the mercy of the state. The bureaucrats decide what prices to charge for needed supplies (food, fertilizer, seed) and what prices to pay for output. Discriminatory policies drove thousands of private farmers off the land and, between 1974 and 1977, cut privately held hog supplies by a seventh.

Credit : The nub of Poland's difficulties is that it has become addicted to Western imports but no longer has the means to pay for them. To increase meat production, it needs outside grain. Its factories now depend on Western equipment. But new credits have dried up and lackluster exports have further cut Poland's purchasing power.

Today, Poland's economic and political crises feed on each other. The government has increased wages and shortened hours as part of its political settlement with the trade union, Solidarity, but production is declining. In the West, this would produce inflation. In the East, where prices are fixed, shortages result. But government attempts to renege on its commitments or to raise prices as a way of sopping up purchasing power provoke new crises.

Clearly, extra credits from the West would ease the strains. But Poland's needs are massive. Even a trade surplus with the West wouldn't provide an automatic solution. Interest payments on outstanding loans alone amount to a fourth of Poland's exports to the West. Poland's normally optimistic central bank now projects a need for $10 billion in additional loans by 1987.

Private Western banks (which hold about 60 percent of Poland's debt) and governments (which guarantee or hold the rest) will clearly have to reschedule repayment of existing loans. The alternative is to declare them in default and risk never getting the money back. But the issue of further loans to Poland has, so far, eluded them.

It is largely a political matter, but the mechanics of extending additional credits appear awesome.

First, there is the division between bankers and the governments. The bankers meet in London, the governments in Paris -- a separation as symbolic as it is geographic. Banks aren't in the business of political gambling, even if governments are. But the governments have their own problems. Could the Reagan administration propose $1 billion for Poland when it's chopping spending for food stamps?

And there is a final, massive obstacle: an understanding with the Soviets.

That they don't want to invade is already clear. Intervention would jeopardize delivery of the Western technology needed to develop Siberia's natural gas deposits. Not do the Soviets want the burden of Poland added to their already considerable political and economic problems. But the mutual interests in rescuing Poland pale before conflicts over other Soviet objectives: reimposing strict party discipline; having the Poles use Western credits to repay Soviet bloc debts.

All this is a good commentary on detente. Critics notwithstanding, it has restrained the Soviets and loosened their control over their satellites. But it has not created a more stable world. No one can guess what will happen in Poland. But among specialists, there seems to be a rule of thumb: The more they know, the less optimistic they are