Congressional Democrats went on the offensive Tuesday against the Bush administration’s handling of intelligence and post-war Iraq, sensing a political opening on the security issue that has bedeviled the minority party for 22 months.

Led by Senate Minority Leader Tom Daschle (D-S.D.), Senate Democrats prepared to offer a series of amendments designed to put Republicans on the defensive, most prominently a proposal to form an independent commission to study a series of alleged intelligence lapses.

“We have become more and more confused over the course of the last several days with regard to the conflicting information provided by the administration on these and other key issues,” Daschle said in a floor statement. “We must find a way with which each of these questions can be clarified and for the administration to come forth with a clear acknowledgement of the need for this clarification is essential.”

Daschle’s statement was his strongest public questioning of the administration on foreign policy matters since his March 17 address that sharply criticized President Bush’s “failed diplomacy” — a rebuke that brought national condemnation of Daschle for criticizing the commander-in-chief two days before the invasion of Iraq.

During the past four months, Republicans have repeatedly claimed that Daschle’s March statements would be front and center in their campaign to oust him next year. But Democrats believe that they have the high ground on the issue, particularly since the series of conflicting statements from the Bush administration for the past week over the President’s now-rejected State of the Union claim that Iraq had tried to purchase uranium in Niger.

“There is a significant issue of credibility,” said Sen. Jon Corzine (N.J.), chairman of the Democratic Senatorial Campaign Committee.

A Democratic strategist indicated he expected the DSCC to begin an e-mail campaign very soon that would be designed to generate petition signatures calling for a bipartisan investigation or possibly an independent commission.

While Republicans protested that Democrats and the media were focusing on the small mistake of the uranium intelligence ending up in the presidential address, Democrats grew increasingly heated in their condemnations of the Bush administration, moving beyond the organized portion of their attacks.

As Sen. Edward Kennedy (D-Mass.) was delivering a blistering attack at the Johns Hopkins School of Advanced International Studies across town — “they put a spin on the intelligence and a spin on the truth” — Democrats one by one were standing up at their Tuesday luncheon in the Lyndon Baines Johnson Room off the Senate floor to denounce the administration.

At least eight different Senators spoke out against the administration’s handling of intelligence at the luncheon, running the ideological spectrum from Sen. Dianne Feinstein (D-Calif.) to Sen. Russ Feingold (D-Wis.). There was a general consensus that Democrats need to seize this crack in the Bush veneer to force the administration to deliver answers on the Iraq situation, people in the room said.

The California Democrat said in an interview following the Democratic meeting she relied on U.S. intelligence reports to help make her decision to vote to allow Bush the authority to wage war against Iraq. But now, Feinstein said, she is “beginning to question the judgments made.”

“I have reviewed that intelligence. If you reviewed the intelligence you have every reason to believe that Iraq had weaponized chemical and biological weapons,” said Feinstein, a member of the Senate Select Committee on Intelligence.

She suggested that at the very least Democrats on the Intelligence panel should launch their own probe.

“My strong feeling is, the Democrats on the committee ought to come together and do our own investigation,” she said, adding that she thought it would be “difficult” for GOP lawmakers to conduct any probe. “I think it is very difficult. I think it is very difficult if Republicans are in control.”

Emerging from the luncheon, Sen. Kent Conrad (D-N.D.) said a large majority of the Caucus supported the formation of an independent commission to study the alleged intelligence miscues, something beyond the reviews being conducted by the Intelligence and Armed Services committees.

“I think there’s a pretty strong consensus that there needs to be an independent commission,” Conrad said.

An amendment to form an independent commission is likely to be offered on the appropriations bill funding the Defense Department, currently being debated on the Senate floor.

It would likely be tasked to study six areas of intelligence that have come under scrutiny in recent weeks, including the Niger-uranium claims and Defense Secretary Donald Rumsfeld’s pre-war boast of knowing where Iraq’s weapons of mass destruction were being held — even though no WMDs have been found more than 10 weeks after Bush declared serious combat operations over.

Republicans showed no signs of willingness to give in to the Democrats, with Senate GOP Conference Chairman Rick Santorum (Pa.) accusing Democrats and the media of “missing the forest for a tree” in focusing on “one piece of information” in the attacks on the administration.

But senior Democrats indicated that the proposal for an independent commission to study intelligence was just one area where Democrats would push the White House. They pointed to an amendment that Sen. Robert Byrd (D-W.Va.), ranking member of the Appropriations panel, was offering to limit the amount of time members of the National Guard spend overseas.

Sen. Byron Dorgan (D-N.D.), a member of the Appropriations subcommittee on Defense, is drafting an amendment that would compel Bush to respond to Congress with an estimate of what the cost will be to stationing troops long-term in Iraq, with the estimate coming to Congress no later than July 29.

In his floor speech, Daschle lashed out at Republicans for not including any spending for the post-war activities in Iraq and the ongoing war on terrorism in the Defense appropriations bill, likening that to a “legislative Never-Never Land.”

In his post-luncheon remarks, Daschle said he had not personally decided whether he would support forming an independent commission, but said he was not sure if the current Congressional reviews are enough to restore public trust in the intelligence-gathering process.

“The question is, is that sufficient or is there something more needed,” he said, alluding to the potential that Central Intelligence Agency Director George Tenet may have been “the fall guy” for the uranium remarks in the State of the Union address.

Walking the political tightrope of running for re-election in a state where Bush remains popular, Daschle said that he had not singled out Bush or any individual for blame and he was just trying to raise questions.

“I don’t think I was critical,” he said while entering the luncheon after his floor speech. “I just think it’s very important we get answers. I’m not prepared to lay blame.”

Indeed, in none of Daschle’s comments did he even utter the words “President Bush”, nor did he make a direct reference to the president. At one point, he signaled support for Bush by saying he didn’t believe any president would intentionally mislead the nation on the eve of war.

Still, even as Democrats noted that they could feel the momentum shift, Daschle said he expected another round of attacks from conservatives. “What makes you think they ever stopped?” he asked.

Meanwhile, House Democrats will huddle next week in a special Caucus meeting to plot strategy on White House intelligence failures in the war on Iraq, the first such planning session in at least two months.

Members will likely meet Tuesday in a closed-door session led by Rep. Ike Skelton (D-Mo.), ranking member on the Armed Services Committee.

While House Democrats have individually been hammering on the Bush administration for its Iraqi foreign policy, they have not yet unveiled a Caucus-wide plan to address the topic. Minority Leader Nancy Pelosi (D-Calif.) has encouraged Members to focus on the gaps in intelligence and the lack of a U.S. plan for rebuilding Iraq.

“We encourage Members to talk about it, but not in partisan way,” said one leadership aide. “We want them to talk about it a responsible way.”

Democratic Caucus Chairman Bob Menendez (N.J.) said the special Caucus will focus on national security overall, with an emphasis on the current situation in Iraq. The goal, he said, is to help Members move toward firmer positions on post-war Iraq.

“Things have transpired and there’s a whole host of questions about the post-combat period,” said Menendez. “It seems to me it raises a series of real concerns about what is our strategy here, how long do we intend to stay, what intelligence are we using to determine the security of our troops and what’s happened to Saddam Hussein?”

Meanwhile, a small group of vocal Democrats has already begun to lead the charge. The self-named Iraq Watch Group has spent the last five weeks using the House floor as a venue to slam the White House over Iraq.

Rep. Bill Delahunt (D-Mass.), one of the four Members in the group, said the goal is to pressure the Bush administration to respond to the unanswered questions about the conflict.

“It’s time to say, ‘where are we going?’” Delahunt said. “We’re trying to encourage the administration to be very clear about defining where we are going.”

Freshman Rep. Rahm Emanuel (D-Ill.), another member of the group, said the effort is to highlight what may not be getting adequate attention in the mainstream media.

He said the group is merely trying to point out concerns such as the recent loss of life in Iraq and the lack of a long-term plan. Reps. Neil Abercrombie (D-Hawaii) and Joe Hoeffel (D-Pa.) are also in the group.

“These are real issues that need to be discussed,” Emanuel said.

Mark Preston and Erin P. Billings contributed to this report.