President Bush's decision to end recognition of rebels battling Cambodia's Vietnamese-backed government _ and open talks with Vietnam instead _ is being welcomed in Congress, but some lawmakers say it doesn't go far enough. ``U.S. policy requires overhaul and intensive effort, not tinkering and fleeting attention,'' Senate Majority Leader George Mitchell, D-Maine, said Wednesday. He called past policy ``a dismal failure.'' Sen. David Boren, D-Okla., chairman of the Senate Intelligence Committee, called for an end to covert U.S. aid to Cambodia's rebel coalition. Secretary of State James A. Baker III announced Wednesday in Paris that the United States would withdraw its support for the three-party coalition that is fighting the Vietnamese-installed Phnom Penh government. That coalition includes the Khmer Rouge, which was responsible for more than 1 million deaths during its reign in Cambodia in the 1970s. Baker also said the United States would begin a dialogue with Vietnam about the need for a political solution to Cambodia's civil war, and would allow U.S.-sponsored humanitarian programs _ including $5 million in aid for children _ to go forward inside Cambodia. The moves were seen as adjustments to a new reality in Cambodia, where a potential takeover by the brutal Khmer Rouge has become a larger worry than fears of encroachment by neighboring communist Vietnam. But in a letter to Mitchell, Baker also said ``it is more important than ever to provide U.S. materiel support for the non-communist resistance, who should not be undercut just as they seek to provide the only non-communist alternative in free elections.'' The United States now provides $7 million openly to the resistance for non-lethal supplies and an additional $13 million a year in covert military aid for the coalition, according to intelligence sources. Both payments are under attack in Congress, because while the aid ostensibly supports the coalition faction of Prince Norodom Sihanouk, critics say it at least indirectly helps the Khmer Rouge, which is the country's strongest military force. Several opponents of U.S. policy said continuing the aid was inconsistent with other moves by the administration. ``The administration has eliminated the rationale for their policy of support for the non-communist resistance, but on the other hand has increased its resolve to provide assistance. That's a contradiction,'' said Rep. Chester Atkins, D-Mass. Citing reports that the Khmer Rouge is gaining ground on the battlefield, Mitchell said: ``There is simply no excuse to delay additional action'' that would go beyond Baker's announcement. Among actions Mitchell sought was direct U.S. talks with the Phnom Penh government of Hun Sen, rather than his Vietnamese sponsors in Hanoi, who are in turn supported by the Soviet Union. And he said Bush should be more willing to apply pressure to China, the chief supporter of the Khmer Rouge, and to do so publicly. ``The Chinese leadership must be made to understand that it stands entirely alone in support of genocidal forces,'' he said. Boren did not directly refer to the covert military aid program that goes through his Intelligence Committee, but he said that all U.S. support for the resistance should be handled openly. ``Any future debate on our policy toward Cambodia should be in the Foreign Relations Committee, not in the Intelligence Committee,'' which meets behind closed doors, Boren said. The intelligence panel voted June 28 to cut off the covert aid program beginning Oct. 1. Boren said he assumed the policy shift is ``a signal that the administration would no longer be seeking any aid that could be even indirectly helpful to the Khmer Rouge.'' That will require the administration to shift its budget request to support humanitarian programs and democracy-building moves, he said. Under U.S. pressure, the United Nations has awarded a seat to the Cambodian resistance coalition and denied formal recognition to Hun Sen. Baker said the United States also was changing its policy toward the Cambodian U.N. seat.