It was finally too much for U.S. Secretary of State James Baker to overlook. Confronted by evidence that the Khmer Rouge, under the leadership of Pol Pot, has made military gains in virtually every province of the country, and with congressional support for Washington’s policy crumbling, Baker cut his losses. He modified a 15-year policy of shunning Vietnam and proposed direct talks with Hanoi, aimed narrowly at settling the Cambodian conflict. Baker hoped that shift–perhaps presaging a thaw in relations with Vietnam–would satisfy mounting pressure from Congress and in the press. Baker also said he would withdraw Washington’sashington’s recognition of the Cambodian seat in the United Nations if it includes the Khmer Rouge. “We want to do everything we can to prevent a return of the Khmer Rouge to power’” he told reporters. Even he had to admit that at this late date, Pol Pot’s forces might prevail.

Since the fall of Saigon in 1975, American policy has been chained to the cold war. After Vietnamese troops invaded Cambodia in 1978, President Jimmy Carter committed U.S. support to the loosely organized rebel factions that opposed Hanoi from bases along the Thai border. The domino theory was still alive in Southeast Asia. China argued that the Soviets, having created a puppet state in Vietnam, were now using Hanoi to set up a puppet state in Cambodia. Later administrations agreed–and supported rebel forces diplomatically and with U. S. military aid, some of which, critics say, has made its way to the Khmer Rouge.

It was a policy that intentionally ignored one important reality: by far the most powerful of the rebel factions nominally headed by the anti-communist Prince Norodom Sihanouk was the Khmer Rouge. And that force shared with its coalition partners only the desire to oust the Vietnamese-installed government now led by Prime Minister Hun Sen. The Khmer Rouge has softened its rhetoric leaders call the policies that led to the killing fields “a mistake” and espouse democracy and market economics but its brutal tactics are unchanged.

Those tactics still prove effective. When Vietnam retreated with its at least 70,000 troops last fall, Pol Pot’s forces advanced. With the Khmer Rouge making gains almost every day, Baker–who flies to Indonesia this week for a meeting of the Association of Southeast Asian Nations–was left with no choice but to revise policy or face a repeat of history that would leave Washington with a measure of the blame. Baker’s solution lies in direct negotiations with Hanoi.

Congress was doing its own rethinking. Last month the Senate Intelligence Committee voted to halt the annual $10 million in covert aid to the resistance. Sihanouk’s reputation was slipping sharply: the General Accounting Office last week revealed that he used $64,249 in humanitarian aid to train orphaned children as a paramilitary force. Congress, suspicious that American aid intended for Sihanouk ends up with the Khmer Rouge. called for change.

Changing that reality will take more than talks with Hanoi. Last week in Paris the United States, Britain, France, China and the Soviet Union moved closer to an agreement on a U.N.-supervised peace plan for Cambodia. Ideally, Beijing will cut off arms supplies to Pol Pot and Moscow will keep Vietnamese expansionism in check. Yet because the region already is so heavily armed, the leverage the outside powers can apply may be too little, too late. “If you built a wall around the Indochina Peninsula and didn’t allow a single gun to get in,” says Douglas Pike with the University of California’s Institute of East Asian Studies, “it wouldn’t have a strategic effect on the fighting in Cambodia for about five years.” The task left to the negotiators is how to wall in Pol Pot.