Sixteen years on, Congress seems to be getting genuinely close to forcing itself into a fresh debate on how to prescribe the use of military force against terrorism.

Writing a new war authorization will not happen before the end of the year, meaning those deliberations would be influenced by the dynamics of the midterm election campaign. But proposals to force the issue onto the agenda have the potential to blossom into sleeper hits on this summer’s remarkably blockbuster-deprived roster of consequential legislation.

A unified Congress, especially in the first year of a new president on the same team, would normally be far along by now in advancing its biggest legislative priorities. But other than the beleaguered and battered measure to remake health care policy in a Republican mold, the party remains remarkably stuck on its big-ticket items.

The self-inflicted impasse would be eased, if only a little bit, should a bipartisan consensus solidify behind a measure the House endorsed last week — on a voice vote with powerful Republican hawks and prominent Democratic doves in vocal support.

The measure’s advocates describe it as a “baby step,” but if the Senate also adopts the proposal, it would nonetheless amount to the biggest step Congress has taken since the aftermath of the 9/11 attacks toward redefining the United States’ ground rules for when to wage war in a world significantly different from 2001. It would likewise be the most lawmakers have done in the intervening years to reassert the legislative branch’s role in setting and financing those policies.

“The war-making power of Congress is slipping away from us,” said Rep. Tom Cole of Oklahoma, a GOP leadership ally who wrote the amendment in order to forestall momentum for a more aggressive anti-war proposal.

“Sooner or later, Congress needs to take responsibility,” he told the House, because “we have slipped into almost endless warfare in a lot of places that none of us anticipated we would be.”

Rep. Jim McGovern of Massachusetts said fellow Democrats were backing the language as an interim compromise.

“After 16 years, we have already arrived at sooner and later,” he said. “Our troops and their families deserve more than silence from a Congress that has no qualms about sending them to war but fails to have the political courage to take a vote.”

The provision was added to the annual defense authorization bill, which the House passed last week and the Senate is set to debate before recessing for the summer. It would give President Donald Trump a one-month deadline for detailing his strategy and his spending needs for defeating the Islamic State, al-Qaida and the Taliban — and his legal rationale for committing troops and weapons to those efforts.

The effect would be to compel Trump to either reiterate, or abandon, the position of his administration and its two predecessors. Under the authorization for the use of military force, or AUMF, enacted one week after the Sept. 11 terrorist attacks, military intervention is permitted anywhere in the world where terrorists are threatening.

Striking back

The AUMF, which has no end date, permits military strikes against any nation, person or organization that had anything to do with 9/11 or any connection to the attackers, “in order to prevent any future acts of international terrorism against the United States.”

The law was cited as the rationale for more than 40 deployments in more than a dozen countries by Presidents George W. Bush and Barack Obama, and already by Trump as the legal justification for the campaign against ISIS and this spring’s air strike in Syria.

Proponents of Cole’s measure say that, whether Trump decides he’s empowered to keep relying on the 2001 law or not, the legislation would fuel what seems to be increasing bipartisan momentum in favor of debating a replacement.

The starkest evidence of that came three weeks ago, when the House Appropriations Committee voted to put the current AUMF on a 240-day path culminating in repeal, which would have compelled Congress to come up with a new authorization before the next election.

That proposal — and the bipartisan applause following its voice vote approval — was a symbolically important breakthrough for Democratic Rep. Barbara Lee of California. She cast the solitary vote in Congress against the AUMF in 2001, presciently arguing it would spawn a sprawling and limitless military conflict, and has been working ever since to limit the law’s application.

Speaker Paul D. Ryan has made clear the language will be deleted before the House debates the annual defense spending bill, which could be next week. Ryan said such an important policy decision should be considered on its own and not catch a ride on a behemoth appropriations measure.

But it’s also the case that a replacement AUMF that’s capable of garnering solid majorities in the House and Senate has proved elusive, and another internecine feud over a high-profile issue is about the last thing that Republican leaders on either side of the Capitol are seeking these days.

“The failure to bridge differences and to pass a new AUMF could create a false impression of disunity during a time of war,” Sen. Bob Corker, the Tennessee Republican who chairs the Foreign Relations Committee, said at a hearing last month.

Congressional response

Two years ago, Obama asked Congress for fresh authority to take on the Islamic State, eventually proffering the language he wanted. But it was never put to a vote because hawks in both parties concluded it was overly restrictive, doves in both parties concluded it was overly broad — and others from both parties simply wanted to shy away from having to cast any vote.

The degree of congressional caution remains palpable. The most prominent senators in the effort to update war authority, last year’s Democratic vice-presidential nominee Tim Kaine of Virginia and Republican Jeff Flake of Arizona, have not found a single co-sponsor for their legislation, for example. (It would permit five years of military action in just a handful of countries against al-Qaida, the Taliban and ISIS, with the president allowed to expand the scope only if Congress agreed in advance.)

Cole, one of the Republicans who spoke out in favor of Lee’s plan in committee, drafted his language as a middle ground that could jump-start the debate without forcing it to finish.

Only 38 of today’s senators and just 22 percent of today’s House members (94 of them) were in Congress at the time al-Qaida hijackers toppled the World Trade Center, crashed into the Pentagon ablaze and dive-bombed into a Pennsylvania field.

Plenty of the lawmakers who’ve arrived since have no desire to be compelled to vote on a war authorization, because it would force them to put a fine point on their foreign policy views and live with the life-and-death consequences forever.

But plenty more are eager for such a debate. Some are principally driven by a desire to put their clear-cut interventionist or pacifist views on the record. Others are eager to rein in an unpredictable president, who at the same time has been delegating significant authority to military commanders. And for others, the driving motivation is to reclaim for Congress some more of the balance of war powers.    

Finally, there is the argument for a new AUMF expressed by the Pentagon. The chairman of the Joint Chiefs of Staff, Gen. Joseph F. Dunford Jr. told Congress last month: “It would send a loud and unmistakable message to our young men and women deployed that the people at home in the form of the Congress support what they’re doing.”