Rep. Mike Rogers, chairman of the House Intelligence Committee, wants to see Congress approve the president's pitch to take military action in Syria, but he said the administration has failed at wooing Capitol Hill.
"I think it's very clear he's lost support in the last week," the Michigan Republican said on CBS's "Face the Nation."
Rogers' comments on Sunday marked a stark contrast to the optimism he expressed a week ago, when he said on CNN he believed Congress would "rise to the occasion" and pass the president's proposal.
Rogers blasted the Obama administration on Sunday for doing an "awful job" in making its case, saying administration officials are not focusing enough on how Syria's ties with Iran could be potentially damaging to the United States.
He also criticized the president for traveling to the G20 summit in Russia last week without calling Congress back from recess to have a national security debate over whether to take military action in Syria.
"The way it happened was mystifying," Rogers said, referring to the president's proposal August 31 for congressional authorization. "He announced it and then left."
The Senate Foreign Relations Committee passed a rewritten authorization measure this week. Lawmakers officially return to Capitol Hill on Monday from their month-long summer break, and the Senate could vote on the resolution as early as Thursday or Friday - or it could drag into the weekend or next week.
It's unclear when or whether the House will vote on the resolution, as Republican leaders have said they will act after the Senate.
While the administration sent three of its top officials - Secretary of State John Kerry, Defense Secretary Chuck Hagel, and Chairman of the Joint Chiefs Gen. Martin Dempsey - to two congressional hearings last week and held multiple classified briefings, Rogers said members of Congress still did not have enough opportunities to weigh the evidence.
"It is a confusing mess up to this point, and that has been, I think, their biggest challenge on what is an incredibly important issue," Roger continued.
To drive home his point that the White House is out of touch with Congress, he bashed the administration for sending National Security Adviser Susan Rice to brief Congress during the same week that marks one year after the attack on the U.S. Consulate in Benghazi, Libya. Rice has come under sharp criticism by Republicans for her statements a few days after the September 11, 2012, attack, when she suggested it came after a protest against an anti-Muslim video produced in the United States.
"And they're trying to win votes. I mean the credibility gap there is huge," he said. "They need to regroup here, think about where they want to go and make this about America's national security," he said.
Rice is scheduled to attend closed intelligence briefings for lawmakers on Monday and Wednesday.
White House Chief of Staff Denis McDonough, who took part in television interviews with five networks on Sunday, said he has spoken with dozens of members of Congress and "not a single one rebuts or refutes the intelligence and the evidence."
The question they face, he said on CNN's "State of the Union," is whether Syria's regime should "be held to account for carrying out this activity."
"What the president said is, if members of Congress want to answer that question, to say that there should be consequences for this action, then they're going to have to vote yes for the authorization," he said.
Speaking on "Fox News Sunday," he argued "it's too early to come to any conclusion" about how Congress will vote.