WASHINGTON (AP) -- Sen. Hillary Rodham Clinton cast a vote in favor of the U.S. invasion of Iraq that would later come to haunt her presidential ambitions.
Now, a new crop of senators eying the White House -- Republicans Marco Rubio, Rand Paul and Ted Cruz-- will face a similar choice over authorizing military action in the Middle East.
A vote in favor of President Barack Obama's resolution authorizing a three-year offensive against the Islamic State group and affiliates would give the potential candidates a share of the responsibility for the outcome of military action in a combustible region. And as Clinton learned well, the public's support for a military campaign can quickly fade, making the long-term implications of the vote difficult to predict.
Obama asked lawmakers this week to approve a request with no geographical constraints. It would bar "enduring offensive combat" -- intentionally vague language that some lawmakers fear leaves open the prospect of a U.S.-led ground war.
Obama is barred from a third term and while Clinton is the presumptive Democratic frontrunner, the Republican race to succeed him is wide open. Rubio has support among the establishment, Paul is a favorite of liberterians and Cruz is a champion of the anti-tax tea party.
While polls show support for Obama's request, Republicans are treading carefully.
Among Republican hopefuls in Congress, Rubio has been perhaps the most specific in outlining his views, saying he opposes the president putting constraints on his ability to use military force against an enemy.
"What we need to be authorizing the president to do is to destroy them and to defeat them, and allow the commander in chief -- both the one we have now and the one who will follow -- to put in place the tactics, the military tactics, necessary to destroy and defeat ISIL," Rubio said.
A spokesman for Paul said Friday that the senator is reviewing the legislation but has not decided on how he would vote. Cruz has called for Congress to "strengthen" the legislation by making sure the president is committed to clear objectives. He also has suggested the authorization should include a provision to directly arm the Iraqi Kurds, but it is unclear what other changes he wants to see.
Despite Americans' war weariness, there is public support for formally authorizing the mission. An NBC News/Marist poll released Friday showed that 54 percent of respondents want their member of Congress to vote for Obama's request.
The military campaign against the Islamic State militants began six months ago, and Obama is, in effect, seeking Congress' approval retroactively. He has said the current mission is legally justified under the 2002 authorization President George W. Bush used to start the Iraq war -- the resolution that Clinton voted for.
By the time Obama and Clinton faced off in the 2008 Democratic primary, the Iraq war was deeply unpopular. Obama saw Clinton's vote for the military conflict as a way to draw a distinction with his better-known rival, arguing that while he was not in the Senate in 2002, he would have voted against giving Bush the war powers.
The 2002 vote and its political implications have continued to shadow the way lawmakers have responded to war-power requests.
In 2013, Congress balked at Obama's request to authorize strikes in Syria and never held a vote. And while congressional leaders pushed the president for months to seek authorization for the Islamic State campaign, lawmakers insisted Obama be the one to actually draft a resolution.
As with Obama's current request, there was public support for Bush's Iraq resolution in 2002. A Gallup Poll a few weeks before the high-stakes vote found that 57 percent of Americans said Congress should "pass a resolution to support sending American ground troops to the Persian Gulf in an attempt to remove Saddam Hussein from power in Iraq." About 38 percent said it should not.
As the Iraq war dragged on, and the death toll and financial costs mounted, the conflict became deeply unpopular.
By the time Clinton and Obama were facing off for the Democratic nomination, surveys showed a majority of Americans believed going into Iraq was the wrong decision -- a warning for potential 2016 candidates trying to read the tea leaves ahead of their own war powers vote.
AP writer Ken Thomas and AP News Survey Director Emily Swanson contributed to this report.
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