Lugar said news reports and his committee's own contacts with U.S. diplomats indicate that there are many opinions within the Bush administration on how best to approach the talks.
"Each of these divergent opinions may have some validity and may deserve to be debated as part of the policy-making process," Lugar said. "But if our policy is to be effective, our ultimate course must be internal consistency and must be explainable to our allies."
Senator Joseph Biden, the highest-ranking member of the committee from the opposition Democratic Party, spoke more strongly. He described the U.S. approach as a "failure," and said the Bush administration had isolated itself from its partners in the six-way talks.
"Right now, no matter what you say, they're not with us," Biden said. "They're with us generically, but they don't think we've gone far enough [in offering incentives]. Individually, we've been importuned by leaders from those countries saying: 'What's the deal? What are you guys doing?'"
But a government expert told the Foreign Relations Committee yesterday that the Bush administration is cooperating with its partners -- and believes it is already on the best path to North Korean disarmament.
Christopher Hill, the assistant secretary of state for East Asian and Pacific affairs, said U.S. negotiators have repeatedly told North Korea that Washington's only objective is to denuclearize the Korean Peninsula. Pyongyang, however, still needs persuading.
"I think it's fair to say that they [the North Koreans] are not convinced yet that they have to do away with this program," Hill said. "And I think they are sort of testing our mettle, they're testing to see whether we're going to get into endless arguments, questioning, with our partners -- they're waiting to see whether we're going to start negotiating with each other or with ourselves to sweeten the pot for them. And so they feel there's some advantage in waiting."
Biden and other senators have expressed doubts as to whether Russia and China are using their considerable leverage to pressure Pyongyang.
Hill said he was unsure whether Russia was truly committed to the stated goal of getting North Korea to abandon its nuclear program. "The question we have is to some extent the same question we have of the Chinese, which is: Given Russia's historical ties to North Korea, given the fact that they have rather close political connections, in many cases personal connections, and certainly they have some economic connections, the question is, are they using all of their leverage? I think we have made very clear that we think everybody should be using whatever leverage they have," Hill said
If there is no breakthrough in talks, the United States may eventually try to persuade the United Nations Security Council to impose sanctions and further isolate Kim's government.
But Hill said Washington would take that course only if it had a good chance of success. China, which has veto power in the Security Council, opposes sanctions in virtually every country.