President Obama said over the weekend that he has decided the U.S. should launch a limited strike on Syria for using large amounts of chemical weapons on its civilians on Aug. 21 — a claim both the U.S. and France are making while the United Nations conducts its own investigation. In a surprise move, however, Obama also said he will ask Congress to authorize the use of military action against Syrian President Bashar al-Assad's government. (Watch Obama argue his case above)

Obama's decision to go to Congress is as risky as it is unexpected. Since John Adams requested congressional approval to attack France in 1798 — and in the 10 subsequent authorizations of military action and 11 formal declarations of war — "no U.S. president has ever been turned down by Congress when asking to use military force," say Michael C. Bender and Roxana Tiron at Bloomberg News. "Obama doesn't want to become the first."

But Congress seems as divided over military action in Syria as the general public, so it's not at all clear that Obama will get his wish for congressional approval. He does, however, seem almost certain to get his other stated wish: A robust debate. Congress won't formally re-convene until September 9, but the White House has already started classified briefings for lawmakers, and the Senate is beginning committee-level hearings on Tuesday.

Whether Congress will approve of Obama's request for force is only one of the big questions surrounding what The Washington Post's Paul Kane and Ed O'Keefe predict will be "the most tumultuous foreign policy debate on Capitol Hill in more than a decade." Here's a look at what's at stake, and what might happen with Obama's big gamble.

1. What will lawmakers be voting on?
On Saturday, Obama handed a draft resolution of his request for military force to the leaders of Congress. Jack Goldsmith, a top legal aide to George W. Bush, argues at Lawfare that Obama's request of authorization for the use of military force (AUMF) is overly broad. "It authorizes the president to use any element of the U.S. Armed Forces and any method of force," Goldsmith says. "It does not contain specific limits on targets — either in terms of the identity of the targets (e.g., the Syrian government, Syrian rebels, Hezbollah, Iran) or the geography of the targets."

As the history of the 9/11 AUMF shows, and as prior AUMFs show (think about the Gulf of Tonkin), a president will interpret an AUMF for all it is worth, and then some. [Lawfare]

Ilya Somin at The Volokh Conspiracy agrees that the wording is "very broad" in some ways, but notes that it's narrow in its focus on Syrian chemical weapons and other weapons of mass destruction. In any case, she adds, "Congress doesn't have to 'take or leave' Obama's proposed wording." Lawmakers could "adopt a narrower or broader authorization for the use of military force," limiting the scope or timeframe of the approved action.

In the House, where anti-war Democrats are already making common cause with anti-interventionist Republicans, there's a better chance that if Obama gets any resolution through, its scope will be "checked by Capitol Hill in a way that gives Congress a stake in the outcome," says W. James Antle III at The American Conservative.

2. Will Congress vote yes?
This is probably the most pressing question, and the answer is anyone's guess. Obama got a boost on Monday when two of the Senate's most prominent Republican foreign policy hawks — Sens. John McCain (R-Ariz.) and Lindsey Graham (R-S.C.) — gave their backing to his requested authorization following a meeting at the White House. But the Senate isn't really Obama's big obstacle; the House is.

Sarah Binder at The Monkey Cage looks at recent academic research into the politics of military-force votes, and isn't overly optimistic for the White House. "Few scholars still believe the adage that 'partisan politics stops at water's edge,'" she notes, and especially in today's hyper-polarized Washington, it's a good bet that "Obama will prevail in the Democratic Senate but face a much rockier road in the GOP House. War politics in Congress might closely resemble domestic legislative battles."

That could turn out really badly for Obama. The Wall Street Journal's Gerald F. Seib argues that Obama is essentially "gambling his presidency on the proposition that he can achieve the very goal that has proved most elusive to him for more than four years: A bipartisan consensus in a bitterly divided Congress." But Obama does have a viable path, Seib says:

The formula for legislative victory starts not with the opposition Republicans but with his own Democrats, runs through the still-powerful pro-Israel caucus, and ends with a band of Republican hawks who have been far more eager for action in Syria than has the president now seeking their help. [Wall Street Journal]

3. Which wing of the GOP holds sway: Hawks or isolationists?
How House Democrats will vote is an open question — many have signaled their opposition to any intervention in Syria's civil war. But the bigger drama, says Jonathan Martin in The New York Times, is "which wing of the Republican Party — the traditional hawks, or a growing bloc of noninterventionists — has the advantage in the fierce internal debates over foreign policy that have been taking place all year."

If McCain is leading the hawks, the most prominent noninterventionist is Sen. Rand Paul (R-Ky.). In another sign of where the real fight will be, Paul is reportedly going to concentrate his lobbying efforts to defeat the resolution in the House. The politics — especially how potential 2016 presidential candidates vote — will be fascinating.

4. Is Obama's big gamble worth it?
The president and his administration have some tough arguments to sell: That Congress should authorize an attack Obama argues he doesn't need congressional authority to execute; that the intelligence is solid, unlike before the Iraq War; and that a strike on Syria that doesn't fundamentally undermine Assad will do more good than harm.

Fred Kaplan at Slate argues that Obama's "monumental gamble" is worthwhile — even though it seems pretty clear that "if Congress votes no, he won't launch an attack."

Obama has assembled a small coalition of foreign allies who have said they'll join in an attack, including France, Australia, and — most important — Turkey. But this isn't enough. And, again, this isn't a matter of legal nicety. It's a matter of political legitimacy, which will be needed to convince Assad that there's determination behind the first few airstrikes — and to provide ballast in case the attack doesn't have much effect. To gain some measure of legitimacy, Obama at least needs domestic support. [Slate]

The Week's Tom Rogan, on the other hand, argues that Obama's big gamble is a terrible idea and an even worse precedent. "By going to Congress, Obama might have placated his domestic critics, but he's weakened his office and he's endangered American interests," Rogan argues.

The New York Times editorial board says that taking the question to Congress is the right thing to do, but adds a big caveat:

If he is to win congressional support, Mr. Obama and his top aides will have to explain in greater detail why they are so confident that the kind of military strikes that administration officials have described would deter President Bashar al-Assad of Syria from gassing his people again... rather than provoke him to unleash even greater atrocities. They will also have to explain how they can keep the United States from becoming mired in the Syrian civil war — something Mr. Obama, for sound reasons, has long resisted — and how military action will advance the cause of a political settlement: The only rational solution to the war. [New York Times]

5. Will this set a precedent for future presidents?
Obama's decision to ask Congress for authorization "appears to be more in keeping with the kind of executive-legislative collaboration envisioned in the Constitution," says David Rothkopf at Foreign Policy. That may be "appealing to the war-weary and war-wary," but for better or worse, Obama has just "reversed decades of precedent regarding the nature of presidential war powers."

Whether you prefer this change in the balance of power or not, as a matter of quantifiable fact he is transferring greater responsibility for U.S. foreign policy to a Congress that is more divided, more incapable of reasoned debate or action, and more dysfunctional than any in modern American history....

More importantly, what will future Congresses expect of future presidents? If Obama abides by this new approach for the next three years, will his successors lack the ability to act quickly and on their own? While past presidents have no doubt abused their War Powers authority to take action and ask for congressional approval within 60 days, we live in a volatile world; sometimes security requires swift action. The president still legally has that right, but Obama's decision may have done more — for better or worse — to dial back the imperial presidency than anything his predecessors or Congress have done for decades. [Foreign Policy]

The Volokh Conspiracy's Somin disagrees. "With the important exceptions of the Kosovo and Libya conflicts, presidents usually have sought congressional authorization for all but very small nondefensive uses of force," she says. "And rightly so, as a matter of both prudence and constitutional law."

Yale Law professor Stephen L. Carter largely agrees. "The transfer of authority from the legislative branch to the executive over the past century has been, on the whole, a terrible thing for the U.S. republic," and is largely to be blamed on "a Congress that will not protect its own prerogatives," he says at Bloomberg View. And Obama's decision to go to Congress "will do little to change that dynamic."

It isn't as though a recalcitrant legislature forced his hand. Obama's seeming reluctance to act without legislative approval will do nothing to handicap his successors. Quite the contrary: If Congress rejects his request, future presidents will simply go back to acting on their own — daring the legislators, [Teddy] Roosevelt-like, to stop them. If, on the other hand, Congress gives Obama what he wants, we can be sure that this president, or some future one, will find another military purpose to which the resolution can be put. [Bloomberg View]