US will bolster Cambodia's noncommunist resistance forces. Reagan meeting aims to help Sihanouk with key UN vote

President Reagan and other United States officials meet today with Prince Norodom Sihanouk in a show of support for the one-time - and possibly future - leader of Cambodia. A flurry of initiatives on all sides shows a general willingness to bring peace to Cambodia. But key actors have real differences on priorities and paths to a solution.

A see-saw of diplomatic maneuvers aims to prevent, on the one hand, a potential return to power of the Khmer Rouge, and on the other, continuation of the 10-year Vietnamese occupation that ended the brutal Khmer Rouge rule.

A microcosm of that contest is the tug-of-war between Prince Sihanouk and the Marxist regime that Vietnam backs in Cambodia. Sihanouk's troops are allied with those of the Khmer Rouge and another noncommunist group in a tripartite resistance. In the event that the estimated 100,000 to 120,000 Vietnamese troops leave Cambodia, the resistance wants Sihanouk to head a transition government that would include leaders of the Vietnam-backed regime.

To bolster Sihanouk, the US plans to beef up financial support for the noncommunist factions, say administration sources. At present, Washington gives $3.5 million a year in nonlethal aid to Sihanouk's estimated 12,000 to 20,000 fighters.

Added US support at this time, even if backed by only a few more dollars, will help the Cambodian resistance coalition in a tough political test at the United Nations in early November.

Sihanouk and his Southeast Asian friends are trying to rally international support for a new resolution on Cambodia. Last year they got 117 nations to call for the immediate withdrawal of foreign - read Vietnamese - troops. This year they are also introducing new ideas for a final settlement of the Cambodian problem.

Some observers say this year's draft could win less support than the earlier resolution. With various Cambodian peace talks going on and peace gestures from Hanoi, fewer nations may be ready to condemn Vietnam. The new draft also makes indirect reference for the first time to preventing a Khmer Rouge takeover. It calls for the ``nonreturn to the policies and practices of the past.'' Lobbying is already intense in preparation for a UN vote in several weeks.

Sihanouk and the Khmer Rouge, as the two main coalition partners, are expected to keep Cambodia's seat at the UN. But a reduction in support would weaken Sihanouk's hand in his third round of peace talks with the pro-Vietnamese Cambodian regime.

Those talks will be held in Paris on Nov. 5 with Hun Sen, the Hanoi-backed prime minister of the People's Republic of Kampuchea (Cambodia). Sihanouk has invited the leaders of the two other resistance forces and the Khmer Rouge as well as former Prime Minister Son Sann to participate.

The talks will focus primarily on how to share power both before and after a proposed internationally supervised election in Cambodia. But Hun Sen's freedom to negotiate a compromise is seen as being limited by Vietnam.

Meanwhile, another forum is in action on Cambodia. This one, nicknamed JIM, involves Vietnam, Laos, and six of their noncommunist neighbors in the Association of Southeast Asian Nations, or ASEAN, as well as the Cambodian parties. A working group meeting will be held next week. It follows a first gathering in July when, for the first time, the issue of Vietnamese withdrawal was linked by ASEAN countries to preventing the Khmer Rouge from retaking power.

That linkage angered China and Thailand, the two countries most responsible for keeping an estimated 35,000 Khmer Rouge guerrillas in action inside Cambodia. They see the Khmer Rouge as the best lever to ensure a Vietnamese pullout. However, several other ASEAN nations believe one must start to build firebreaks to ensure that the Khmer Rouge can't dominate, once Hanoi leaves.

The key issue in the JIM talks is whether Hanoi will allow an international peace-keeping force into Cambodia during its withdrawal. Such a force would be expected to stop the Khmer Rouge threat.

``I imagine that the Khmer Rouge are right now hiding arms in the jungle and waiting for the day they can take over,'' says Malaysia Prime Minister Mahathir Mohamed. ``I doubt that any [Cambodian] government would be able to control'' the Khmer Rouge, and thus one needs international peace keepers.

A key sign of Vietnam's intentions has been the pace of withdrawal. Apparently under Soviet advice, Hanoi announced last June that 50,000 troops would leave by year-end. US analysts say only 5-6,000 have left so far. Vietnam claims 15,000 have exited, but blames a slowdown in the withdrawal to monsoon rains.

A few Western analysts in Bangkok contend, however, that Vietnamese forces have had some tough fights in recent weeks with Khmer Rouge forces, perhaps delaying a pull out.