America is at war. What war, exactly, isn't quite clear.

Sen. Rand Paul, R-Ky., tried to get Congress to answer this question this week, as the Senate debated this year's military authorization bill.

Unless the Senate took up his amendment to rescind the 2001 and 2002 Authorizations for the Use of Military Force in Afghanistan and Iraq, he said, he would use every dilatory tactic at his disposal and make everyone's life unhappy for at least the 30 or so hours of floor time that Senate rules permit as the world's greatest deliberative body took up the new defense authorization bill. This is a semi-serious threat, considering that there are hundreds of amendments that senators are demanding votes for.

We don't need to get into the parliamentary maneuvering to recognize that Paul is absolutely right on this issue. The U.S. military is currently fighting wars all over the Muslim world, taking on ISIS and other enemies, on the strength of authorizations Congress passed in 2001 and 2002. That is ancient history: In about a year, the Pentagon will likely deploy soldiers in Afghanistan who were born after the post-9/11 authorization.

The Obama administration tried to use the 9/11 resolution to justify military intervention in Syria. It served a very specific purpose at the time. It was never in anyone's wildest nightmares intended to become a perpetual catch-all justification for carrying on any conflict against any terrorists anywhere in the world, let alone bad-actor regimes.

The terms of the 2001 resolution were arguably not as limited as they should have been, but they were nonetheless quite specific. It authorized the use of...

...all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons.

At best, the ancient and obsolete AUMF from 2001 might facially justify continued fighting in Afghanistan against the Taliban, which "harbored" al Qaeda at the time of the 9/11 attacks 16 years ago. But even there, the case is pretty weak. It doesn't even cover Islamic State forces newly active in that country.

It affronts both reason and the prerogative of Congress to justify our sprawling Middle East war by reaching back to an overly broad 2001 resolution that isn't even country-specific. Not one of the members of Congress who voted for that resolution in September 2001 expected it would still be invoked to justify the continued war in Afghanistan after two separate presidents had been term-limited out of office. For context, about the same amount of time passed between the Cold War U.S. invasion of Granada and 9/11 as has now passed since the September 2001 attack and the Authorization for the Use of Military Force.

And of course beyond Afghanistan, there is no reasonable way of tying this resolution to a justification of any war elsewhere.

If President Trump wants to engage the services of the military with a true legal mandate, he needs to turn to Congress and ask for an authorization that is both transparent and appropriately limited in time and space, so as not to bind the U.S. to any more long-term conflicts than are absolutely necessary.

Congress shouldn't micromanage a U.S. war, but Congress needs to make clear exactly what war we are fighting.

For example, to the extent that the U.S. has a valid justification for its current military involvement in Syria, Congress should authorize it on its own merits. It should not base its decision, as the Obama administration tried in 2013, on the merits of an earlier fight that is not directly related.

It is no small thing to go to war. It is one of the gravest responsibilities that our elected leaders have, and it is a responsibility that the Founding Fathers believed Congress had a major role in. When sending the world's strongest military force into action, our leaders ought to cross every t and dot every i. It's not as if Congress has something more important to do than to mind the wars into which it has sent American servicemen and women to fight, kill, and potentially die.

Sixteen years of open-ended and sophistic justification for war is more than enough. It's time for Congress rescind the 2001 authorization. It should then formally authorize the continuation of any other conflicts it deems worthy using more limited and specific language that prevents another perpetual state of war.

If Congress does anything else, if Congress meekly decides to look away and pretend the 2001 war is the same as our current war, it is shirking its gravest duty.