That latter prerogative, established at a time when warfare was waged with musket balls, has been rendered almost meaningless in the modern era. Congress has not issued a formal declaration of war since 1942 — even though the decades since have seen the U.S. military engaged in Korea, Vietnam, Grenada, Panama, Iraq, Bosnia, Kosovo, Afghanistan and Libya.
“Congress really does not share in that decision until after the fact. The war-making power has passed to the president,” said Lee H. Hamilton, a former Democratic congressman from Indiana who was chairman of the House foreign affairs and intelligence committees. “A lot of people, including myself, have been critical of Congress for being too deferential.”
Americans still view the commitment of U.S. forces to be a decision — and a burden — that should be shared between the executive and legislative branches of government, even when citizens themselves are not so certain what the proper course of action should be.
In a new NBC News poll, respondents were divided on whether the United States should intervene in the wake of alleged chemical weapons attacks by Syrian President Bashar al-Assad’s regime.
But opinion in the poll was clear when asked whether Obama “should or should not be required to receive approval from Congress before taking military action in Syria.” Nearly eight in 10 said he should.
Those kind of numbers have persisted on similar questions going at least as far back as the Vietnam era. And it is a position that also draws support from both sides of the aisle in Congress— something that rarely happens in these hyper-partisan days.
“I feel like they’d be in such a better position to call us back and get Congress to take some ownership,” said Sen. Bob Corker (Tenn.), the ranking Republican on the Senate Foreign Relations Committee. “I listen to some of the debates that take place on foreign policy, and so many of them can be sophomoric, silly and not even substantive in regards to the issues the nation is dealing with. I think that’s because Congress has never really had to own up to these issues.”
The concern on Capitol Hill has been intensified by the decision of Britain, normally a stalwart comrade in arms, not to participate in action against Syria.
While there is broad consensus that the Syrian government should be held accountable for the actions it is believed to have taken against its own people, “we are also bound by the ethics of democracy and international lawfulness,” Rep. Jim McDermott (D-Wash.) said in a statement Thursday that reflected the sentiment of many liberal members of Congress. “Our constitutional checks and balances must be honored.”
Obama’s stance is also complicated by past statements about when a president should defer to Congress.
As a senator running for president in 2007 — one who often touted his early opposition to the Iraq war — Obama was asked by the Boston Globe whether the commander in chief had the power to bomb Iran without approval from Congress.
“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,” Obama said.
“In instances of self-defense, the president would be within his constitutional authority to act before advising Congress or seeking its consent,” he added. “History has shown us time and again, however, that military action is most successful when it is authorized and supported by the legislative branch.”
As president, however, Obama found himself challenged by lawmakers of both parties over the use of U.S. forces in a 2011 military operation in Libya.
His administration argued that the action did not require congressional approval because the United States was acting in a supporting role in an international effort.
As the Vietnam War was winding down, Congress attempted to reassert its authority with the passage of the 1973 War Powers Resolution. It calls for the president to get congressional authorization of military action within 60 days after it begins, or start withdrawing forces.
But in practice, the War Powers Resolution “amounted to little more than toy handcuffs,” historian Arthur Schlesinger once wrote.
That is because nearly every administration over the past 40 years has indicated it believes the resolution to be unconstitutional. Courts have been reluctant to intervene in what they regard to be a political matter. And Congress has not been willing to cut off funds when the law is not followed.
Presidents — including Obama in dealing with congressional furor over Libya — often have said they are notifying Congress “consistent with,” but not “pursuant to,” the War Powers Resolution. That is language that allows them to defuse congressional opposition, without conceding that the law is valid.
But Hamilton added that the current state of the Congress — in which political sentiment is more diffuse and factionalized — has also made it more difficult for a president to figure out where the Capitol Hill consensus really lies.
“You have no mechanism for the president to consult, and that is a considerable problem,” Hamilton said.
Nor does congressional support at the outset of combat guarantee that Congress will remain behind the president if things go poorly or if the operation does not turn out to be the brief and limited strike that Obama has promised.
“Even assuming he could get a blessing, it doesn’t provide that much political cover,” said James Lindsay, a senior National Security Council aide during the Clinton administration who is director of studies at the Council on Foreign Relations
Scott Clement and Ed O'Keefe contributed to this report.