In September, President Obama announced the American campaign to "degrade and ultimately destroy" ISIS, an operation defined in large part by what it wouldn't entail, namely "putting boots on the ground." Two months later, with ISIS stalled but not deterred, the whole American strategy against the militant group may be coming under review.

One of the top priorities is the question of what the U.S. posture should be toward Syrian leader Bashar al-Assad, whom Obama said in 2011 must go but who remains in power three years later. Many administration critics, both at home and abroad, have argued that the Syrian president is benefiting from the American strategy of directing focus and firepower on Assad's enemies in the Syrian civil war. American-led airstrikes have targeted not just ISIS, but also two separate groups in Syria that are battling the Assad regime.

Doing little to counter Assad's campaign of barrel bombs and mass civilian murder has come at a cost. The moderate (or "moderate") rebels the United States is seeking to empower in Syria feel alienated by American actions at best, and imperiled at worst. The U.S.-led coalition's focus on ISIS has freed up the Syrian government to launch attacks elsewhere in the country. Meanwhile, Turkey, the most important and reluctant ally in the international coalition, has refused to offer meaningful assistance unless plans to oust (or least confront) Assad make their way into the American strategy.

The challenges of this multi-sided war may now be more apparent to U.S. officials than they were earlier this fall, as Obama is reportedly reassessing a regional strategy that has more or less sidestepped the Assad question. This conversation, according to CNN's Elise Labott, has taken the form of at least four high-level security meetings in which the American policy on Syria and its plans to battle ISIS have come under review. "These meetings, in the words of one senior official, were 'driven to a large degree [by] how our Syria strategy fits into our ISIS strategy,'" writes Labott. (Even the anonymous sources in the article can't agree on the right name for the enemy, using ISIS instead of the administration's preferred acronym for the Islamic State, ISIL.)

On Thursday, Defense Secretary Chuck Hagel denied the claim that the Obama administration is changing its policy vis-à-vis Assad.

Of course, just weeks ago The New York Times reported that Hagel himself had criticized the White House strategy on Syria in a memo to National Security Advisor Susan Rice. What was he miffed about? The fact that Assad was benefiting from American action against ISIS.

So what happens if the United States does change course? There are strategic benefits to removing Assad from power, of course, but there is no end to the political and military complications either. While the American-led coalition has targeted Islamic State forces and installations in Syria from the sky, they've done so without having to confront Assad's considerable air forces. If the United States throws the Syrian regime into its crosshairs, the mission in Syria will likely get considerably thornier.

Then, of course, there is the matter of Russia and Iran, who may be theoretically on board with the effort to stop ISIS, but who have sought to arm and keep afloat the Assad regime throughout the three-and-a-half years of the Syrian civil war and have blocked every international effort to oust him from office. Both countries have given no sign of relenting on that front.

Meanwhile, degrading ISIS remains as difficult as ever. On Thursday, an audio tape was released of what appears to be Islamic State leader Abu Bakr al-Baghdadi taunting the United States just days after he was reported injured in an airstrike. Add to this confounding mix a statement on Thursday by House Armed Services Committee Chair Buck McKeon that directly challenged the president's pledge for "no boots on the ground" and threatened to veto an Authorization for the Use of Military Force in a congressional hearing.

So my fundamental question is: how can you successfully execute the mission you’ve been given—to 'degrade and ultimately destroy' ISIL—when some of your best options are taken off the table? Mr. Secretary, both of your predecessors, Bob Gates and Leon Panetta, have stated that we need boots on the ground if there's to be any hope of success in the strategy.

McKeon then managed to rope the legendary college basketball coach Mike Krzyzewski into his critique, noting that "Even Coach 'K' told an Army conference last month that declaring we won’t use ground forces is like telling your opponent you’re not going to play your best players."

Speaking of everyone's best players, the Associated Press is now reporting that ISIS and al-Qaeda are putting aside their considerable differences to fight their mutual foes in Syria. Right now, that list includes Bashar al-Assad and the United States.