The malevolence of sectarian politics has finally caught up with Ladakh, the Shangri-La up in the Himalayan Mountains where time has stood still for centuries.

Virtually inaccessible a decade ago, arctic-like Ladakh long had been a sequestered model of cultural and political tranquility, where Buddhists and Moslems lived together in rustic harmony and where sectarian and regional differences were as scarce as the vegetation that struggles for life at rarefied altitudes of 15,000 feet and more.

But now, after a spirited election campaign for the region's one seat in the Indian Parliament, a new political assertiveness has emerged along religious lines. By outward appearances, Ladakh remains as phlegmatic as ever, but sectarian tensions simmer beneath the surface, and regional rivalry is noticeably on the increase.

The phenomenon calls into question -- in this case, at least -- the conventional wisdom that what is known in India as communal conflict is an outgrowth of pressures from overcrowding, poverty, despair and the social constraints of the caste system.

Ladakh, roughly the same size as West Virginia, has a population of 132,000, about 54 percent of whom are Buddhist and 45 percent of whom are Moslem. It represents a microcosm of the kind of communal and regional divisions that have strained the fabric of the Indian union for years.

Although poverty is pervasive in the desertlike terrain, Ladakh, with about two persons per square mile, has one of the lowest population densities in the inhabited parts of the world. Caste divisions are unheard of here, and the sturdy, industrious Ladakhis -- of Mongolian and Aryan origin -- are legendary for their happy, outgoing nature and for their longevity.

Early caravan traders and Christian missionaries, awed by the rugged beauty of Ladakh, often described it in their writings as a lofty paradise, seductive in its tranquility and spiritual atmosphere and unspoiled by alien cultures.

For the most part, that remains true today. Nobody remembers when the last violent crime was committed, and a new jail on the outskirts of this district capital has remained virtually unused.

Over the years, election campaigns have come and gone without serious controversy, as the Leh-based Buddhist majority exercised its dominance and elected a succession of Congress (I) representatives to state and federal government.

This year, however, Moslems concentrated in Kargil, in the westernmost part of the Ladakh territory in the Indian state of Jammu-Kashmir, decided to challenge longstanding Buddhist dominance in the parliamentary balloting. Ladakh was snowbound when most of the other 21 Indian states voted Prime Minister Rajiv Gandhi's Congress (I) Party to power in national elections held last December, so voting here was on April 24.

While tensions between the two religious communities have been mostly subdued, they occasionally have flared into open conflict.

Last year, bands of Buddhist youths, including monks, stormed into antique shops in Leh operated by Moslem traders from Srinagar. The youths demanded that the Moslems stop sale of Buddhist religious artifacts because they viewed it as an affront to the faith. The Moslem shopkeepers sought police protection.

Two years ago, Buddhists demanding special tribal status clashed with police, and two protesters, including a monk, were killed by police gunfire.

But political and religious leaders of both faiths agreed that the current tensions have been fueled by the April 24 parliamentary election, held under the most extreme conditions.

The sectarian battle lines were drawn in March when Kashmir's leading Moslem politician, former state chief minister Farouk Abdullah, began campaigning heavily in the Kargil district on a platform that promised an end to Buddhist domination in Ladakh.

"For 37 years, there has always been a Buddhist Leh representative in Parliament. Kargil has never been represented. It is time for a change," said Abdullah, who was ousted from the state's top post last year in a party revolt engineered by the Congress (I) Party.

Ladakh's Moslems, Abdullah said, have become increasingly bitter over what they feel has been favoritism toward the Buddhists by the central government. The Congress government, he said, has poured millions of rupees into desert development projects in the Leh district, while ignoring Moslem areas of Kargil. Buddhists are given preference in civil service jobs, he charged, and Leh was awarded an airfield and a radio station while Kargil received neither.

Buddhist political and religious leaders here charge that Abdullah's campaign was designed to polarize Ladakh along sectarian lines for political gain, and they say that to a degree the ploy worked.

"Ladakhis are basically very peaceful people, but like anywhere else we have some troublemakers in the religious communities. There hasn't been much of a problem between Ladakhis, but since the Moslem National Conference became involved in the election, some people from the Kashmir Valley have come to try to communalize Ladakh," complained Kushok Bakula, Ladakh's chief Buddhist lama, or monk, in an interview in his hillside monastery here.

Signs of election fever were abundant throughout the countryside surrounding Leh, where Ladakhis stood patiently in long lines to cast their ballots.

The Congress candidate from the Leh district, P. Namgyal, defeated Moslem National Conference candidate Qumar Ali by 7,900 votes. The Buddhist candidate had a 15,000-vote edge in the predominantly Buddhist Leh region, while the Moslem candidate beat his Buddhist opponent by 7,500 votes in the predominantly Moslem Kargil region. Scattered voting between the zones favored the winner.

At one polling booth in the village of Chochot, Mohammed Akbar Ladakhi, a Moslem, said he was saddened by the sectarian overtones of the election.

"This is the first election fought in Ladakh on a communal basis. Why do we have to have this? Take me. My wife is Christian. My maternal grandparents are all Buddhists. My father's side is all Moslem," said Ladakhi, a retired civil servant and Congress supporter.

Where the current sectarian tension will lead normally tranquil Ladakh is uncertain. Many Ladakhis already regard their region as separate from the Indian union, and concern has been raised by some here that polarization between the Buddhist majority and the Moslem-dominated state government of Kashmir could lead to increased demands for a special autonomous status for Ladakh. That, in turn, could be troublesome for the government of Prime Minister Rajiv Gandhi. Parts of the strategic territory are still in Chinese possession as a result of a 1962 invasion.

Ladakh was an independent Buddhist kingdom until it was annexed by the Moslem-majority princely state of Kashmir in 1833, becoming part of India after Jammu-Kashmir acceded to India in 1947. The Ladakhi demand for autonomy dates to 1949 and conceivably could gain momentum if Buddhist resentment over Moslem dominance grows.

However, moderate Buddhist leaders maintain that the tension could be defused if the central government accords special tribal status to all Ladakhis -- Buddhists and Moslems alike. That status would allow privileged access to university appointments and civil service jobs under the Indian government's minorities quota system. They say this remote region would then avoid the kind of open communal conflict that has afflicted much of the rest of India.