It's way too early to know how lawmakers will vote on whether to authorize military action in Syria, in part because much of the mechanics of the debate and the exact nature of President Obama's request to Congress remain unclear.
The Senate will hold committee hearings this week and a full debate and vote the following week, while the House plans to begin debating the issue when it returns to Washington on Sept. 9.
Very few lawmakers have said they will vote for or against military action, because most are waiting to see how the Obama administration makes it case in the coming days.
Based on our reporting and the statements issued by lawmakers in the last 24 hours, here's a general outline of how we believe lawmakers are dividing on the issue of military action in Syria:
The "do it now, already" caucus:
This group includes Sens. Bob Menendez (D-N.J.), Carl Levin (D-Mich.), Bill Nelson (D-Fla.) and Johnny Isakson (R-Ga.), Rep. Peter King (R-N.Y.), House Minority Leader Nancy Pelosi (D-Calif.) and House Minority Whip Steny Hoyer (D-Md.).
In a strongly-worded statement, Nelson said Saturday that "I support the president's decision. But as far as I’m concerned, we should strike in Syria today. The use of chemical weapons was inhumane, and those responsible should be forced to suffer the consequences.”
King sharply criticized Obama for waiting for a congressional resolution, saying that he "is abdicating his responsibility as commander-in-chief and undermining the authority of future presidents. The president does not need Congress to authorize a strike on Syria. If Assad's use of chemical weapons against civilians deserves a military response, and I believe it does, and if the president is seeking congressional approval, then he should call Congress back into a special session at the earliest date. The president doesn't need 535 members of Congress to enforce his own red line.”
The "want bigger military action" caucus:
This group is much smaller and is led by Sens. John McCain (R-Ariz.) and Lindsey O. Graham (R-S.C.), who said Saturday that they agree with Obama that a military response is necessary and that Congress should act as soon as possible.
But then they went a step further: “We cannot in good conscience support isolated military strikes in Syria that are not part of an overall strategy that can change the momentum on the battlefield, achieve the president's stated goal of Assad's removal from power, and bring an end to this conflict, which is a growing threat to our national security interests. Anything short of this would be an inadequate response to the crimes against humanity that Assad and his forces are committing. And it would send the wrong signal to America's friends and allies, the Syrian opposition, the Assad regime, Iran, and the world – all of whom are watching closely what actions America will take.”
The "happy to debate the issue, reserving judgment" caucus:
This is the largest caucus. Most lawmakers in this group, including Sen. Christopher Coons (D-Del.) and Rep. Trey Radel (R-Fla.), agree that the Syrian government's action are deplorable, but that they will withhold judgment until the debate begins in earnest.
“I will review the evidence and arguments with great care before deciding how I will vote on this difficult and important issue," Sen. Angus King (I-Maine) said Saturday.
Radel said that the administration will "need to answer questions on the national security threat facing America, how we prevent our troops from getting dragged into a civil war, and how we are going to prevent the loss of American lives. Finally, the administration must lay out a plan, the end goal and an exit strategy."
Sen. Jeff Flake (R-Ariz.) said in a statement Saturday that he will "review all classified and unclassified information to properly assess the implications of U.S. action and the impact on U.S. interests."
Coons said that he believes some type of military response is justified. But he added in a statement that he "will carefully consider the potential consequences of our actions, and will weigh the input of Delawareans and the evidence presented by the administration and the United Nations.”
The skeptical caucus:
A fair number of Republicans and Democrats in both chambers sit with this group.
Sen. Joe Manchin III (D-W. Va.) expressed a view Saturday that sums up the feelings of many congressional Democrats. "After over a decade of war in the Middle East, there needs to be compelling evidence that there is an imminent threat to the security of the American people or our allies before any military action is taken," he said. "I do not believe that this situation meets that threshold."
Sen. Marco Rubio (R-Fla.) pointedly said Saturday that "The United States should only engage militarily when it is pursuing a clear and attainable national security goal. Military action taken simply to send a message or save face does not meet that standard."
Rep. Robert B. Aderholt (R-Ala.) was especially sharp, saying that Obama's speech "leaves many questions, such as who exactly are the 'good guys' in this conflict? And how is American involvement not the fuel for the fire the Muslim Brotherhood and extremist are trying to ignite throughout the region? Cruise missiles are not a strategy. The president by now should see that foreign policy is far more complex than that."
Others, like Sen. Lamar Alexander (R-Tenn.) had more practical questions. "I’m concerned about the consequences of a military strike in Syria, and what happens with step two, three and four after that. There may be a variety of ways, some military and some not, to show our disgust with the Syrian government’s apparent use of chemical weapons against its own people."
The anti-military action caucus:
This group stitches together an unlikely alliance of tea party conservatives and veteran liberal doves, many of whom still remember the consequences of the Iraq war debate.
Rep. Justin Amash (R-Mich.) is a leading GOP "no" vote, who has spent much of the weekend sharing his views on Twitter:
Americans don't support war in #Syria & neither does Congress. No clear U.S. interest or strategy. We don't want entanglement in this war.
— Justin Amash (@repjustinamash) September 1, 2013
In an interview Sunday on PostTV's "In Play," Rep. Scott Rigell (R-Va.) said that "I do have a bias against" supporting military action. "If I had to vote today, I would vote no. But I also expect to learn from the debate."
As he often does during debates about military action, Rep. Charles B. Rangel (D-N.Y.) said that the U.S. military should reinstate the draft before committing military personnel "to another war."
"Reinstating the draft and requiring women to register for the Selective Service would compel the American public to have a stake in the wars we fight as a nation," Rangel said. "We must question why and how we go to war, and who decides to send our men and women into harm's way."
Follow Ed O'Keefe on Twitter: @edatpost