With the Senate facing a cliffhanger vote on financing Iraqi reconstruction, the White House on Wednesday sent two of its top guns, Vice President Cheney and Secretary of State Colin Powell, to pressure wavering Republicans to give $20 billion to Iraq in the form of grants.

Even as House Minority Leader Nancy Pelosi (D-Calif.) signaled her opposition to the entire $87 billion emergency supplemental, the White House was furiously working the Senate to shore up the GOP vote in what has become a highly significant vote, both strategically and politically.

Kicking all staff out for a Senators-only meeting with Powell and Cheney, the duo delivered a stern warning that President Bush was not going to go for a compromise mix of loans and grants, as some GOP and Democratic Senators had been floating.

“Grants, no loans,” said Sen. Robert Bennett (R-Utah), summing up the message delivered by Powell and Cheney at the Wednesday luncheon. Bennett and most other Senators declined to comment about the specifics of the Powell-Cheney delivery.

Cheney’s pep talk was a sign of how seriously the White House is taking the issue. While he almost always attends the Senate GOP’s weekly luncheon, the vice president is generally deferential and rarely speaks out, Republicans have long said. Instead, he usually takes a seat in the middle table of the ornate Mansfield Room and makes himself available to any Senator who wants to speak to him.

One GOP Senator described Cheney’s short message Wednesday as “very, very forceful.” Speaking a bit longer than Cheney, Powell’s 10-minute presentation focused on the Bush administration’s expectation of winning the upcoming vote of the U.N. Security Council aimed at bringing more nations into the reconstruction effort.

Sen. Trent Lott (R-Miss.) said Cheney struck a tough but appropriate tone given the gravity of the issue. “It wasn’t a lecturing thing,” Lott said, noting that the rarity of Cheney’s pitches to the entire GOP Conference gives each one more weight. “When he does speak, it’s worth listening to,” he added.

But it’s unclear just how much impact Cheney and Powell had, as a handful of Senate Republicans continued working with several moderate Democrats to put together a deal that might seal the fate of the issue. Democratic Sens. Evan Bayh (Ind.), John Breaux (La.) and Ben Nelson (Neb.) appeared to reach an agreement in principle Wednesday with such conservative stalwarts as Sens. John Ensign (R-Nev.) and Saxby Chambliss (R-Ga.) to come up with a package that mixed loans and grants in the $20 billion package.

One GOP Senator questioned whether Cheney would make a final difference in the vote, which is still pending since the final details of the Bayh-Nelson-Ensign alternative were being hammered out by staff Wednesday night. “I don’t know if he changed any minds or not,” the Senator said.

Knowing the numbers were close, Lott said he warned Cheney that the administration may have to face defeat and accept some mixture. “I told him they better be careful because they’re getting on the edge,” he said. “We better have some flexibility.”

Bennett, the Chief Deputy Whip, said the vote was too close to call at this point. “My guess is it’s going to be pretty close,” he said.

Meanwhile in the House, Pelosi announced Wednesday she will oppose the $87 billion war supplemental. Pelosi, who voted against last year’s resolution authorizing force in Iraq, had earlier been leaning toward supporting the measure, but has since has shifted her view.

“The president’s supplemental budget request is an $87 billion bailout for his failed policy,” Pelosi said. “It’s time for the Bush administration to be held accountable for its policy, which miscalculated the risk in post-war Iraq, misunderstood the challenge and misrepresented the facts.”

Pressure has been mounting within the Democratic Caucus to vote against the supplemental, especially among progressives.

The evolution of Pelosi’s position appears to mirror the momentum in the Caucus. Several Members have in recent weeks held one-on-one sessions with colleagues to try to increase the “no” vote. And Wednesday, the Congressional Black Caucus announced unanimous opposition to the bill.

The Minority Leader is at odds with the House’s No. 2 Democrat, Minority Whip Steny Hoyer (D-Md.), who has maintained his support for the bill. Hoyer voted in favor of the supplemental in the Appropriations Committee last week, and was among the House Democrats who backed the resolution last year authorizing the Iraqi conflict.

Senior Democratic aides throughout the Caucus said the expected votes by Pelosi and Hoyer would be indicative of the larger Caucus picture. The Caucus is expected to break almost evenly on the vote.

It would also follow the split on last year’s resolution, which put Democrats in a tough political spot as they tried to craft a coherent message and strategy on the Iraq. House Democrats have and continue to wrestle with how to criticize the Bush administration while remaining supportive of American troops in Iraq.

“We’re in a box,” acknowledged a Democratic leadership staffer.

Amid the split, Hoyer made an 11th hour pitch to Members at the weekly leader’s luncheon to focus their supplemental message on supporting the troops and the Bush administration’s bungling of post-war Iraq policy. Such a message would fit with Democratic House Members who support or oppose the $87 billion spending request.

“Hoyer made a forceful speech,” said one leadership aide. “Regardless of where we come down, there are a lot of failures on policy. There’s a lot of consensus [among Democrats] on that.

“The message can be the same even if we vote different ways,” said the staffer.

Hoyer said earlier Wednesday that even though Democrats will not vote as one on the supplemental, neither will Republicans. He added that Democrats have consistently been unified on other major policy initiatives.

“We have differences, but there are differences in their party as well,” Hoyer said.

But some House Democrats were concerned that the party once again would fall short of unity on a key foreign policy vote.

“At the end of the day the biggest message coming out of this tomorrow will be what the vote is,” said a senior Democratic House aide.