Tim Kaine, a Democrat, represents Virginia in the Senate.

Last week, both the Obama administration and certain members of Congress said that no congressional authorization is needed for U.S. military action in Iraq. I deeply disagree.

The framers of the Constitution gave Congress the power to authorize war. As James Madison wrote, “The constitution supposes, what the History of all Governments demonstrates, that the Executive is the branch of power most interested in war, and most prone to it. It has accordingly with studied care vested the question of war to the Legislature.”

The framers also understood that a president, exercising the powers of commander in chief, might need to act before Congress in an emergency situation. But, in such a case, there must be an imminent threat to the United States, and Congress must subsequently ratify a president’s actions.

In 2001, in response to the Sept. 11 attacks, Congress passed a broadly worded Authorization for Use of Military Force that has been interpreted by the George W. Bush and Obama administrations to authorize military action against al-Qaeda and its associated forces. Congress passed a second AUMF to authorize the Iraq War in 2002.

The Capitol dome is seen on Capitol Hill in Washington. (J. Scott Applewhite/AP)

In the current Iraq crisis, neither authorization applies. The Islamic State of Iraq and Syria (ISIS) is not an al-Qaeda affiliate — in fact, it is openly battling with al-Qaeda in Syria — and administration officials have said that the 2002 AUMF is obsolete and should be repealed.

No one can deny that threats from ISIS, al-Qaeda and other extremist groups across the region are metastasizing. An Iraq that becomes a haven for jihadists poses a threat to the United States. I’m open to hearing the case for military action in Iraq, but first we need a new playbook.

President Obama said in May 2013 that he would work with Congress to update the 2001 AUMF. It is June 2014, and there has been no progress. The White House should submit to Congress a new draft authorization to deal with today’s threats. Now is clearly the time for this debate.

I believe the president must come to Congress for authority to initiate any U.S. military action in Iraq. We should do many things immediately — robust diplomatic engagement, humanitarian aid, strong security assistance for our partners that face a regional threat from ISIS. Specific counterterrorism action, whether overt or covert, should be part of the debate about a new AUMF. But war takes Congress.

Ultimately, the allocation of war powers is based on a value. The nation should not send U.S. service members into harm’s way unless there is a consensus among the civilian leadership — executive and legislative — that the mission is worth it. Ordering people to risk their lives without Washington doing the work necessary to reach a political consensus is immoral.