President Barack Obama’s pursuit of a military strike in Syria has put congressional Democrats and party leaders around the country in a tough spot.

They face loud opposition from war-weary constituents at home and are wary of being pulled into another foreign conflict. But they also are confronted with grim images from Syria of gassed children and the pleas of a president from their own political party to consider the consequences of inaction.

Breaking from Democrats’ long history of being the party typically opposed to military conflict, Obama is pushing for a limited military strike in Syria in response to President Bashar Assad’s alleged use of chemical weapons. House Democratic leader Nancy Pelosi and Senate Majority Leader Harry Reid have rallied behind him.

But some liberal and moderate Democrats, the wars in Iraq and Afghanistan fresh in their minds, have begun joining dozens of conservative Republicans registering their opposition. And many rank-and-file Democrats are undecided on whether to support a congressional resolution for military action, questioning whether it would turn the tide in a bloody civil war, whether it’s in the U.S. national interest and whether it would prompt Assad to retaliate with more chemical weapons.

“We’ve been to this dance before and we saw what happened in Iraq,” said Rep. Bruce Braley, D-Iowa, who says he is leaning against supporting the resolution. “And I have a solemn responsibility to understand what the risks are before I vote to authorize the use of force. What’s the risk to the U.S. and the president’s standing in the world if the Congress votes against the resolution?”

Emerging from a closed-door briefing on Thursday, Rep. Tulsi Gabbard, D-Hawaii, an Iraq war veteran, said she wanted answers about what would happen after a U.S. attack but her own military experience was giving her “great pause” before making a decision.

Rep. Alan Grayson, D-Fla., was resolute in his opposition. “It’s simply not our responsibility,” he said, wearing a tie covered with 1960s peace symbols.

In the Senate, Democrats Chris Murphy of Connecticut and Tom Udall of New Mexico opposed the resolution to authorize a strike when it was up for a committee vote while recently elected Massachusetts Sen. Ed Markey, who succeeded Secretary of State John Kerry, voted present. West Virginia Sen. Joe Manchin, one of the party’s most moderate members, said he would oppose the resolution. More than a dozen Democratic senators are supporting it.

Obama captured the Democratic nomination in 2008 in part because of his opposition to the Iraq war, a position that he used effectively against primary opponent Hillary Rodham Clinton, who as senator voted in October 2002 to authorize the war but then stumbled among anti-war Democratic voters.

Many Democrats in the House first won their seats in the elections of 2006 and 2008, when the party was fueled by voters who blamed President George W. Bush for the enduring conflicts. It is difficult for many of those Democrats to authorize U.S. intervention in a new conflict — even as Obama and Kerry assure them that it will be narrowly focused and not include U.S. ground troops.

“Members are trying to really listen and hear and understand,” said Rep. Gregory Meeks, D-N.Y., who said he was undecided after emerging from a private briefing on the issue Thursday night. “They don’t want to make the same mistake that was made before.”

The deliberations extend into households. Rep. Jan Schakowsky, D-Ill., who opposed the 2002 Iraq war authorization, is undecided this time but has said a failure to hold Syria accountable for the chemical weapons attack would set a “terrible precedent.”

Schakowsky’s husband, Democratic strategist Robert Creamer, wrote in a Huffington Post column last week that the U.S. needs to punish Assad for the use of chemical weapons.

The Syria vote has generated an intense lobbying effort by the left to pressure Obama to stay out of the civil war.

Liberal activists are planning candlelight vigils across the country on Monday night to urge members of Congress to oppose the resolution, and they suggest those who support military action risk political punishment in the future.

“Everyone who positions themselves as a progressive needs to think very hard about what their vote will mean down the road,” said Anna Galland, executive director of MoveOn.org.

At the same time, a large delegation of members representing the influential American Israel Public Affairs Committee, the pro-Israel lobbying group with strong ties to congressional Democrats, plans to press lawmakers on Capitol Hill next week to approve the resolution.

The vote could carry implications beyond this year. House Democrats who represent liberal districts might face primary challenges if they support the resolution. The votes could figure prominently in several key Senate races crucial to Democrats’ effort to maintain control of the chamber during Obama’s final two years.

Incumbents in two closely watched races — Sens. Mary Landrieu of Louisiana and Mark Begich of Alaska — remain undecided. But Sen. Mark Pryor of Arkansas, running for a third term, said in a statement Saturday that “at this time” he can’t support the resolution to intervene in Syria that lawmakers are expected to consider next week.

Among potential 2016 presidential candidates, Clinton said through an aide that she supported Obama’s efforts in Congress. As secretary of state she urged the administration to intervene in Syria, and a speech in Philadelphia on Tuesday could give the former first lady the opportunity to discuss a potential U.S. response. Maryland Gov. Martin O’Malley told reporters last week that there was a need for a “clear understanding of what it is exactly this mission would hope to accomplish.”

Wrapping up a trip to Sweden and Russia, Obama will try to make a full-court press next week, addressing the nation on Tuesday while his administration fans out to briefings and meetings with wavering lawmakers.