The push for a congressional vote ahead of any military strike in Syria is being spearheaded largely by lawmakers who were not in Congress during the run-up to the war in Iraq.
As of Wednesday, Republican Rep. Scott Rigell had collected the signatures of 140 House members demanding that President Obama call Congress back into session to vote before launching an offensive in Syria. And roughly three-quarters of the signers, including Rigell himself, a former Marine elected in 2010 who represents the military-heavy area around Norfolk, Va., came to Congress after the Iraq war had begun. More still had arrived after the Iraq war resolution passed in late 2002.
The same is also true in the Senate, where first-term senators have been among the loudest voices pushing for explicit congressional authorization.
Much of the Congress has turned over since the early 2003 invasion of Iraq, with three wave elections in 2006, 2008, and 2010 sweeping away lawmakers and redistricting eliminating the seats of still others in 2012.
Only 32 current senators served in 2002 during the fall vote on the Iraq war resolution and only 38 were there when American troops launched the invasion in the spring of 2003. In the House, roughly 40 percent of current members -- 172 of them -- were sworn in at the time of the 2003 invasion.
That means that, for many in the current Congress, this is the first time they've experienced the drumbeats of war, outside of the strikes that Obama authorized against Libya earlier in his presidency. And instead of marching in line, the fresh faces are among those most loudly demanding a public debate.
"The U.S. should not take military action without congressional authorization," Sen. Chris Murphy, D-Conn., said this week.
"When and if President Obama makes a decision on Syria, he must immediately call a special session of Congress and persuade the American people that what he proposes is critical to the defense of our nation," Sen. Ted Cruz, R-Texas, added.
Sen. Tim Kaine, D-Va., said Thursday on CNN's New Day that "getting congressional approval is in my view constitutionally required. "
Kaine, Murphy, and Cruz are all Senate freshmen.
When Obama was running for president, he embraced the power of Congress to authorize military strikes, telling The Boston Globe, "The president does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation."
On Thursday, Obama called House Speaker John Boehner to brief him about the developments in Syria, and his top aides prepared to brief congressional leaders on relevant committees in the evening.
It is not clear what is causing the divide between the old guard of Congress and the new, but it is pronounced. Members who were not in Congress pre-Iraq are signing on to Rigell's letter at a faster clip.
For instance, the current chairman of the House Homeland Security Committee, Rep. Michael McCaul of Texas, elected in 2004, has signed the letter calling for congressional input. In contrast, his predecessor as chairman, GOP Rep. Pete King of New York, elected in 1992, has said, "I believe the president can take this action without authorization from the Congress."