People demonstrate against US intervention in Syria in front of the White House in Washington on Tuesday. Nicholas Kamm/AFP/Getty Images

Sue Kelly wishes she could go back to 2002 and re-take her vote to authorize the war in Iraq.

Eleven years ago, Kelly was a moderate Republican congresswoman from New York who, under pressure from the Bush administration, voted with 294 of her colleagues to authorize the war.

"I live every day with that vote," she told Al Jazeera.

Lawmakers were told then too that military engagement would be clean and quick, Kelly remembers, and that Iraqis would greet American troops with open arms. Her vote was later attacked by political opponents and her constituents — she lost her bid for re-election in 2007 after serving in Congress for 12 years.

She hopes the current crop of lawmakers is more skeptical of the administration's case and more aware of the consequences.

"Anybody who votes for it will have to pay the price of carrying the act. That is unnecessary blood on their hands," she said. "It's not any different — they're going to go in there and someone is going to die."

As the unpredictable debate over potential military strikes in Syria rages on Capitol Hill, it's clear that the wars of the last decade are weighing heavily on lawmakers' minds, particularly those who were in Congress when both the House and the Senate overwhelmingly voted to give President George W. Bush the authority to invade Iraq.

Although administration officials have repeatedly said there will be no American boots on the ground and the circumstances are drastically different from Iraq in 2002, members of Congress are reticent to make the same mistakes again and suffer the political consequences.

"It may be irrelevant, but it's unforgettable. It's one of things that lingers on," said former Rep. Connie Morella, one of six Republicans in the House to vote against the resolution in 2002 because she didn't see enough international backing. "People think 'Gee, I made that mistake once, I don't want to make it again.'"

Unlike Kelly and Morella, 162 members of the House of Representatives who were there for the 2002 vote are still serving in Congress (some of them now in the Senate). Of those, 89 voted to authorize the war, and 73 voted against. In the Senate, 32 members from 2002 are still in the chamber, and 23 of them at the time voted for the resolution. It appears fewer of them will be on board with President Barack Obama's request.