Boots on the ground in Syria, combat in Iraq, and an expanding campaign against the Islamic State have thrust the issue of passing a congressional authorization for such military ventures back into the spotlight.

But renewed interest in light of those new developments may still not be enough to spur Congress to take action.

In recent weeks, congressional frustration has been rising with how the Obama administration has been handling the fight against ISIS in Iraq and Syria. Several Democrats are adding their voices to a growing chorus of critics, pointing to Russia’s increasing influence in Syria and the United States’ largely ineffectual efforts to train and equip moderate rebel forces.

The White House said President Obama plans to deploy a small number of special operations forces to Syria to advise rebels Washington deems moderate. (Reuters)

President Obama’s Friday announcement that special operations forces would be heading to Syria inspired several frustrated lawmakers to call more emphatically for a new authorization of military force (AUMF).

“The Administration’s announcement that it will deploy Special Operations Forces into Syria to combat ISIL marks a major shift in U.S. policy,” Sen. Brian Schatz (D-Hawaii) said in a statement. “This shift in policy is a strategic mistake.  Regardless of my views, the War Powers Resolution requires Congress to debate and authorize the escalation of U.S. military involvement in Syria.”

“With the announcement today, we’re going to see the tempo and the scale of American engagement against ISIS step up one more level,” said Sen. Chris Coons (D-Del.) “I think that we are now well beyond of the scope of the 2001 AUMF.”

But the greatest hurdle to Congress setting the terms for U.S. engagement with ISIS may be coming from within its own ranks.

Republicans and Democrats have failed to resolve their differences over what the terms of a new AUMF would be, particularly when it comes to how much force they want to authorize. The White House announced Friday that fewer than 50 special operations forces would be heading to Syria in a non-combat role – though many question whether the advisory roles they will play are not de facto combat functions.

Many lawmakers want to keep combat troops out of Syria at all costs. And there are others who believe the gesture should be stronger, like Sen. Tom Cotton (R-Ark.), who said on CNN Friday that the president’s plans were not robust enough.

Such divisions continue to cripple attempts to move forward with a new AUMF. And it is not clear that the new venture in Syria will galvanize lawmakers to resolve their differences.

Nonetheless, the Senate Foreign Relations Committee is preparing a detailed briefing on the matter this week, according to an aide to chairman Bob Corker (R-Tenn.).

That committee approved an ISIS-related AUMF in 2014 — but it never passed Congress. And that 10-to-8 vote  went straight down the party lines.

“I think there is a concern that this would be become, rather than a principled debate about what’s good for the country, it could fall into a more of a political discussion,” Sen. Jack Reed (D-R.I.),  Senate Armed Services Committee ranking member said on MSNBC Friday, adding it was “appropriate” for Obama to continue operating under the 2001 AUMF.

But Reed explained that “in principle, I think if we could set up the parameters…so that this debate is principled and focused and is constructive and leads to an updated and more responsive AUMF, I’m all for that.”

Obama argues that the campaign against ISIS is legal under the umbrella of the 2001 AUMF that authorized the U.S. military to retaliate against the perpetrators of the Sept. 11 attacks, particularly al-Qaeda. The 2001 AUMF only authorizes “all necessary and appropriate force” against countries, organizations, and people that “planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons.”

The administration has included ISIS under that definition because of historic and long-standing links between the group and al-Qaeda. But last year, al-Qaeda formally disassociated itself from ISIS, so the connection is now tenuous.

While some, like Reed, support the president’s legal argument, few in Congress believe that the current ISIS campaign in Iraq and Syria falls very neatly within that definition.

“I can tell you what it smacks of: mission creep,” said Senate Armed Services Committee Chair John McCain (R-Ariz.) “In a perfect world, we should have a new AUMF but that’s not going to happen, not until the president asks for it, and the president will not ask for it.”

“It is a quagmire – he wants to stay out of it and if I were president, I would have the same reluctance,” McCain added. “But sooner or later, there is going to arise the constitutional problem.”

Obama says he would be open to Congress passing a new AUMF focusing on ISIS. But the version of that AUMF he presented to Congress earlier this year – a three-year authorization to fight ISIS and “associated forces” – didn’t satisfy either Democrats or Republicans calling for Congress to play a greater oversight role.

Sens. Tim Kaine (D-Va.) and Jeff Flake (R-Ariz.) tried earlier this year to push a revised AUMF vote – but their proposal still has not seen floor time.

“I think it’s very much time that Congress revisited the question of this authorization,” Kaine told Defense Secretary Ashton Carter last week, during testimony before the Armed Services Committee on the expanding U.S. Middle Eastern strategy.

An AUMF, Kaine argued, would “provide some underlying legal justification for the ongoing military action.”