House Republicans are poised to reject President Obama’s resolution to authorize military force against Syria absent the administration convincing a strong majority of typically anti-war Democrats to back the legislation.

The proposal hit Capitol Hill Sunday and quickly appeared on life support, as usually hawkish Republicans questioned Obama’s Syria strategy and the GOP’s rising isolationist wing suggested that no amount of cajoling would persuade them to authorize another Middle Eastern military intervention. Nevertheless, Republican sources said the resolution might still pass, possibly with significant GOP support, but only if Obama invests political capital on his side of the aisle and sways House Democrats.

“Republicans will expect the president to round up a lot of Democratic votes and show that he’s committed to his own request,” said a GOP operative with relationships in Congress.

Rep. Devin Nunes, a California Republican who has served on the House Permanent Select Committee on Intelligence for the past three years, told the Washington Examiner that he opposes Obama’s Syria resolution and doesn’t think the votes will materialize — regardless of the president’s personal lobbying and the forceful case for military action the administration has made in recent days. Votes are likely the week of Sept. 9, when Congress officially returns from its summer recess.

Nunes predicted that hardline, anti-war Democrats would join in opposition with skeptical Republicans who might usually be inclined to support military action against Syria to sink Obama’s resolution. Nunes explained that there many Republicans troubled by the broader implications of a Syrian regime that deploys chemical weapons with impunity but opposed to attacking the Middle Eastern dictatorship because they lack confidence in Obama’s military and diplomatic strategy — and distrust his leadership.

“This is nothing short of an unmitigated disaster,” Nunes said Sunday, in a telephone interview. “I may be wrong, but I don’t think the votes are even close.”

Clues to members who could be the hardest to whip might be found in the results of a July vote to curtail funding for the National Security Agency in the wake of revelations about its domestic surveillance programs. The legislation, sponsored by libertarian-leaning Rep. Justin Amash, R-Mich., garnered a surprising 205 “yes” votes in defeat — 218 were needed for passage — including 111 of 200 Democrats, and 94 of 233 Republicans. Nunes voted “no.”

Only 83 Democrats voted against Amash’s NSA amendment, which was cosponsored by Rep. John Conyers, D-Mich., and many more Democratic “yes” votes than that will be needed to ensure the GOP support needed to move Obama’s Syria resolution through the House. House Republicans have struggled to assembly GOP majorities to pass politically charged tax and spending bills, as Obama and House Democrats sat on the sidelines and watched them sweat.

This is a rare case of the shoe being on the other foot. This time, the president and House Minority Leader Nancy Pelosi, D-Calif., have to deliver the votes first — if they want the resolution to clear the chamber. “The Republicans, to me, are in the catbird seat,” a GOP political consultant said. “They have the perfect play.”

Obama announced Saturday that he had decided to use military force to punish Syrian President Bashar Assad's regime in retaliation for the Aug. 21 chemical weapons attack that killed more than 1,400 of its citizens, including hundreds of children. But the president simultaneously announced that he would seek congressional authorization before acting, although he said such approval was not legally necessary.

The administration’s classified briefing for House members and senators, held Sunday afternoon on Capitol Hill, did not appear to satisfy the Democrats or Republicans who attended.

Some expressed concern about the resolution itself, which critics described as overly broad; others remained skeptical of the mission itself. Obama’s resolution could be narrowed to assuage bipartisan concerns about the possibility of open-ended conflict. Ameliorating hawkish Republicans disdain for Obama’s stated strategy of limited military strikes that do not aim to put a significant dent in the Assad regime or contain his weapons of mass destruction, is a much heavier political lift.

“If you want the U.S. military to be involved, there better be a clear objective that involves regime change or containment of the WMD,” said Nunes, who did not attend Sunday’s briefing. “I’ve spent time on this issue, including spending time in the region, and have yet to speak to a military official that said either one of those objectives would be easy.”