It is the job of Congress to decide on force against ISIL

Just before leaving for summer recess at the end of July, the House of Representatives turned to the issue of Iraq. Throughout June, President Obama had steadily increased the presence of U.S. troops in Iraq from an initial 275 to nearly 800. Military force had not yet been used, but the writing was on the wall.

So the House laid down a marker: By an overwhelming bipartisan majority (370-40), members affirmed their constitutional responsibility to decide whether the United States should again enter into combat in Iraq, passing a resolution that said, "The president shall not deploy or maintain United States armed forces in a sustained combat role in Iraq without specific statutory authorization."

Rep. Jim McGovern, D-Mass., one of the resolution's main sponsors, left no doubt as to its purpose. "The time to debate our re-engagement in Iraq, should it come to that, is before we're caught in the heat of the moment," he said. " Not when the first body bags come home, not when the first bombs start to fall."

The bombs have now started falling, a gruesome video of the Islamic State in Iraq and the Levant (ISIL) executing American journalist James Foley as circulated the Internet, yet Congress has still not weighed in. There is still time for clearheaded deliberation and collective judgment on a broad range of options. But that window looks to be closing fast.

What began as a small deployment of a few hundred troops to provide support and security for our embassy personnel quickly grew. On Aug. 8, the president authorized "targeted airstrikes" that he assured Congress would be limited in scope and duration.

Now, in a little more than two weeks, the United States has waged an air war with more than 90 strikes. The mission's objectives have expanded from protecting American personnel to assisting humanitarian efforts, to helping Iraqi forces recapture "critical infrastructure" — a dam more than 200 miles outside Baghdad.

This escalation suggests that the president's other pronouncement about the scope of U.S. military intervention in Iraq will prove more accurate than his assurances to Congress: "This is going to be a long-term project."

This is precisely why the Constitution's framers vested war power in the legislative branch. The elected representatives of those who will risk their lives in the fight must debate the issue and make the solemn decision about whether to enter a war. The president's job is to conduct it, once authorized. This check and balance of power and responsibility is central to the fabric of our republic and ensures that both political branches are accountable to the people.

To date, the president has acted alone, invoking "constitutional authority to conduct U.S. foreign relations and as commander in chief and chief executive."

The Constitution arguably permits the president to act to defend the nation and its citizens against an actual or imminent attack without prior congressional approval. U.S. combat operations in Iraq already exceed that narrow exception.

More troubling, the president's stated rationale lacks any discernible limit on U.S. combat operations going forward. Reminiscent of rhetoric used to justify military intervention in Libya three years ago, the president said recently that the United States has "a national security interest" in making sure that a "savage group [like ISIL] ... is contained, because ultimately it can pose a threat to us."

That rhetoric, and the extent of U.S. military engagement that it implies, has ratcheted up in the wake of James Foley's death and the ISIL's continued indiscriminate and brutal attacks on civilians. According to Secretary of State John Kerry, ISIL "and the wickedness it represents must be destroyed." That can't be done, says Joint Chiefs of Staff Chairman Gen. Martin Dempsey, "without addressing that part of the organization that resides in Syria."

Sad to say, Congress has often been reluctant to own up to its exclusive responsibility to decide when the country goes to war. The House resolution adopted in July was a welcome break with that reluctance.

Now, Congress and the president need to discharge their respective constitutional responsibilities. The president should immediately seek congressional authorization to continue military operations in Iraq, and Congress should reconvene to debate and vote.

We are rapidly approaching a decisive moment. The pros and cons of action can still be weighed, but the debate needs to happen now. The Constitution requires it, and the American people deserve it.