WASHINGTON – An attempt by House Republicans to put forward a new budget proposal was crumbling as soon as it emerged Tuesday, panned by party conservatives and attacked by the White House and congressional Democrats.

House Speaker John A. Boehner outlined the offer as a last-ditch effort to resist having to stomach the bipartisan compromise emerging from the Senate. But it was unclear if Boehner had support for passage or if a House vote would be held later Tuesday.

“We are talking with our members on both sides of the aisle to try to find a way to move forward today,” said Boehner after the morning House GOP meeting, flanked by his leadership team.

The reaction from Democrats was swift and unified.

The White House quickly criticized the offer as “a partisan attempt to appease a small group of tea party Republicans who forced the government shutdown in the first place.”

FULL COVERAGE: The U.S. government shutdown

“The president has said repeatedly that members of Congress don’t get to demand ransom for fulfilling their basic responsibilities to pass a budget and pay the nation’s bills,” said spokeswoman Amy Brundage.

Senate Majority Leader Harry Reid (D-Nev.) said he was “blindsided” by the House Republicans’ “extreme” offer, coming as he and Senate Minority Leader Mitch McConnell (R-Ky.) were narrowing on their compromise proposal. A planned Senate GOP meeting was hastily postponed.

“Extremist Republicans in the House of Representatives are attempting to torpedo the Senate’s bipartisan progress with a bill that can’t pass the Senate – can’t pass the Senate – and won’t pass the Senate,” Reid said.

But Boehner got an unexpected boost from Sen. John McCain (R-Ariz.). The harsh and vocal critic of the tea party wing’s budget strategy condemned the Democrats’ refusal to entertain the House proposal – a sign the Senate’s bipartisan plan may be running into head winds from that chamber’s conservatives.

“It’s piling on – and it’s not right,” said McCain, urging Senate leaders to negotiate with Boehner. “I don’t understand that visceral reaction.”

Democratic leaders from the House were summoned to the White House for an afternoon meeting with President Obama, but it was clear that Boehner was unlikely to pick up support from that side of the aisle to help offset defections of his own.

PHOTOS: 2013's memorable political moments

"I saw a speaker who doesn’t have the votes,” said Minority Leader Nancy Pelosi (D-San Francisco).

House Republicans wanted to get ahead of a quickly developing bipartisan proposal in the Senate by suggesting they could move their own measure Tuesday to end the standoff over the federal budget.

But Boehner’s hard-right flank did not embrace the latest proposal and may ultimately see it as insufficient, leaving the speaker once again facing difficulty in passing anything. His leadership team met later Tuesday.

"The leadership wants to bring something to the floor to show the American people that actually it is the Senate that is dragging its feet and is going to miss the president's imposed deadline and hopefully Congress can take action before that," Rep. Andy Harris (R-Md.) said after the GOP meeting.

The House plan would include stronger measures targeting President Obama's healthcare law, but still represents a major scaling back of GOP demands and may draw opposition from the most conservative Republicans in the chamber.

As Boehner outlined the plan, it would accept key parameters of the emerging Senate deal – reopening the federal government by extending current spending levels through Jan. 15, and raising the nation's debt limit through Feb. 7.

PHOTOS: The battle over Obamacare