WASHINGTON — The moment has been long in coming, but it may finally have arrived.
For the last year and a half, on issues including health care, financial regulation and climate change, Democrats in the House have bent for President Barack Obama. Liberals swallowed hard-to-accept compromises that fell short of their long-sought goals, and moderates cast tough votes that now threaten their re-election prospects as voters revolt against government overreach.
Then, last week, the president asked them to bend yet again — this time to approve more money for his troop buildup in an Afghanistan war that many Democrats oppose.
And once again, lawmakers went to work. On the eve of the vote last week, Democratic leaders compiled a complicated $82 billion package of war funding, disaster aid and domestic spending that achieved the seemingly impossible — meeting the president's request while accommodating the needs of its politically diverse members.
Obama responded with a one-word message that sent shudders through his party on the Hill: veto.
In that exchange, the tension between the White House and the president's Democratic allies spilled over.
Obama has led what historians have called the most productive Congress since President Lyndon Johnson, but he may have a much harder time extracting difficult compromises in the future.
"You've got a lot of people doing a lot of heavy lifting here," said freshman Rep. Gerald Connolly, D-Va. "I don't know that we expected flowers and chocolates," he said. But the president's response "was an unwelcome message."
In recent weeks, the president has expressed growing interest in the remaining items on his legislative agenda, including energy and immigration policy. Both are initiatives whose only hope at passage would require another legislative squeeze from the lawmakers who have already yielded to some of the president's toughest requests.
Yet compromise appears difficult as lawmakers approach the midterm election when they, not the president, must fight for their political lives in a tough electoral climate.
"There's no question we've taken on big policy issues," said Rep. Allyson Schwartz, D-Pa. "Each time we reach a heavy lift we think, 'How are we going to do more?' We do."
Anxious over the deepening economic distress at home and political and military setbacks in Afghanistan, some Democrats see the war as one without end and one they cannot philosophically or economically support.
"I would rather do a little bit more nation-building here at home," said Rep. Jim McGovern, D-Mass.
Rep. David R. Obey, D-Wis., the powerful chairman of the House Appropriations Committee, devised a complicated legislative strategy that appeased liberal lawmakers by allowing antiwar amendments and pleased moderates by paying for a $10 billion teachers' initiative without adding to the national debt.
But the White House was not pleased with the arrangement, threatening late last week to veto the package if it contained any antiwar provisions or cut programs favored by Obama to pay for the teachers' salaries.
The bill now heads to the Senate, and House Democrats are furious at an administration that many see as tone deaf to the political realities facing lawmakers in a November electoral climate that is not expected to be friendly to incumbents.
"I don't give a rip about the administration," said Rep. Dennis Cardoza, D-Calif., whose district in central California faces one of the highest unemployment rates in the nation. "The administration can decide to be with us or not. I'm all about jobs for my district."
Then again, Obama has had a historically successful legislative run, signing into law the economic stimulus package, health care restructuring and, perhaps soon, the Wall Street overhaul, along with a long list of lesser known bills on credit card changes, tobacco regulation and fair pay.
The uneasy mood on Capitol Hill may not matter.
"It is the end of the road," said Matthew Bennett, a vice president at Third Way, a think tank in Washington. "But they're at the end of the list."