For much of President Barack Obama's second term, Congress sought to pass a formal authorization for the war against the Islamic State — both to signal the country’s resolve and to provide a check on the president's unfettered war powers.

That failure to act now means Donald Trump will effectively have free rein to wage what he calls a global U.S. war on radical Islam, a prospect that terrifies many Democrats.


“You could easily see him wanting to ramp up the war on terror and take it to new parts of the globe,” said Rep. Adam Schiff of California, the top Democrat on the House Intelligence Committee. “There are few limits on what he can do.”

Democrats like Schiff worry that without an updated legal framework to govern the war on terror, Trump could turn some of his controversial campaign rhetoric into reality — from vows to bring back waterboarding to killing families of terrorists.

For "an inexperienced president who tweets and gets angry … to have broad war-making power, it’s a dangerous place to be," said Rep. Barbara Lee (D-Calif.), the lone member of Congress who voted against the nation's existing war authorization, which was passed in 2001 but has not been updated since.

Some Democrats are starting to lay the groundwork for a new push next year for a war resolution, but the chances of passage remain low. Without a new resolution, Trump is likely to have almost unlimited powers as he takes over U.S. military involvement in Iraq, Syria and Afghanistan and potentially ratchets up ongoing efforts to hunt down and kill suspected terrorists the world over.

Senate Foreign Relations Chairman Bob Corker (R-Tenn.), who would play a major role in shepherding any potential authorization for the use of military force through Congress, said that while he supports the idea of a new war resolution, he does not see it being a big priority for the incoming Trump administration and the new Congress.

“They've got other fish to fry,” Corker said. “I believe that the AUMF we have right now gives the president the legal basis to do what's being done against Al Qaeda and ISIS and others.”

Trump has not yet laid out what he would want in a potential new war resolution but signaled in May he might seek one. Asked by Fox News' Bill O'Reilly whether he would favor a new “declaration of war,” Trump responded: "It wouldn't bother me at all doing that. We probably should have done that in the first place.”

Trump's pick for defense secretary, retired Marine Corps Gen. James Mattis, wrote in a blog post last year for the Hoover Institution that a new resolution, "supported by a majority of both parties in both houses of Congress, will send an essential message of American steadfastness to our people and to the global audience." He argued for a broad resolution with no deadlines, geographic limits or restrictions on potentially using ground combat troops.

Some Democrats are hoping Congress will pass a new war authorization to rein in Trump, by clearly defining the strategy and goals of the war against the Islamic State, also known as ISIS. But the partisan divisions that scuttled previous efforts still remain.

“I felt like it was urgent under President Obama, who I supported, and I feel like it’s urgent under President Trump, and I was on the other ticket,” said Sen. Tim Kaine of Virginia, the 2016 Democratic vice presidential nominee. Kaine has been a top proponent of a new war authorization, teaming last year with Sen. Jeff Flake (R-Ariz.) to push for votes on a bipartisan measure setting limits for the war against the Islamic State.

Kaine said he is continuing to seek Republican support for a new military authorization measure and has been discussing proposals with Senate Armed Services Chairman John McCain (R-Ariz.).

“We're going to talk about it. We continue to talk about it,” McCain said of his discussions with Kaine. “He's got a point. Congress' role, particularly as far as conflict is concerned, has been reduced significantly. There's no doubt about that.”

Congress last year tried and failed to pass a resolution setting parameters for the war against the Islamic State, with the White House and lawmakers putting forward a half-dozen proposals — some that would have covered a three-year time frame, confined operations to Iraq and Syria and placed limitations on the use of U.S. ground combat troops.

The effort collapsed in a partisan dispute, with Democrats pushing for tighter restrictions and Republicans saying they didn’t want to curb the president’s ability to fight terrorists.

Without a new military authorization, the ongoing U.S. war on terrorism will continue to be bound by the measure approved 15 years ago after the Sept. 11 terrorist attacks.

That existing resolution authorizes force against those who aided or took part in the 2001 attacks — and has generally been interpreted as targeting “Al Qaeda and associated forces.” It has no time frame or geographic limitations — and the Bush and Obama administrations have invoked it as justification to go after suspected terrorists all over the world, from the Philippines to the Horn of Africa, and even on the “high seas,” according to the Congressional Research Service. It has been the legal justification for drone strikes, special forces raids and many other types of U.S. military operations.

The Obama administration has taken an expansive view of which groups can be targeted under the 2001 AUMF, applying it to the Islamic State even though the terrorist network did not exist when the resolution was passed and has publicly feuded with Al Qaeda.

Some of the proposals for an updated military authorization against the Islamic State would have repealed the 2001 resolution, while others — including the White House's proposal — would have left the 2001 resolution in place.

Trump, who has pledged to avoid nation-building and regime change while ramping up efforts to wipe out terrorism, will be able to point to Obama-era precedents to justify military operations against suspected terrorists in just about any part of the world, if he chooses to do so.

Earlier this month, the Obama administration issued a 66-page report detailing its legal framework for the global war on terrorism, including its views on who can be targeted under the 2001 military authorization.

But Trump will have wide leeway to interpret the 2001 resolution as he sees fit.

Of the 100 senators in office when lawmakers cast votes on the post-9/11 war resolution, it is likely that only 22 will be serving next year.

“Perhaps many of my Republican colleagues who were concerned about not tying the next president’s hands — now that the next president is Donald Trump — they may come to regret that decision,” Schiff said. “He’ll have very wide leeway to target any terrorist organization with any connection to Al Qaeda, anywhere, and that’s deeply troubling.”