"The only way this battle ultimately is won is with troops on the ground, but they need to be Arab troops," Paul said without directly answering the question. "The president's strategy so far is not working."
When preparing to run for president, it's not uncommon for politicians to carefully skim the edges of contentious debates.
"Rand is admittingly and actively running for president. He is on all the shows," said Sen. Jim Inhofe, R-Okla. "I have no way of getting into his head and knowing what his strategy is, but perhaps that might be influencing him."
If Paul really wants to avoid answering questions about the Obama administration's resolution, he's got his work cut out for him. The three-page AUMF, after all, was only released publicly Wednesday morning. But as he considers a response, Paul must weigh appearing tough against ISIS with staying true to his more libertarian foreign policy principles.
Paul's early reluctance to directly critique the president's plan speaks to Paul's long-term foreign policy gamble.
While Sens. Marco Rubio and Lindsey Graham have called for a broader AUMF, and Sen. Ted Cruz has asserted the president's AUMF is flawed, Paul's past positions indicate he is more likely to take a different approach. During his Senate rise, Paul has wrestled with a path that allows him to appear engaged on foreign policy flashpoints while also giving him room to exercise the pragmatism he's known for when weighing the limits of the U.S.'s ability to police the globe.
From drone strikes to arming Syrian rebels, Paul has been more cautious than some of his colleagues who look at U.S. intervention as the key to stability around the world.
"Intervention created this chaos," Paul said on the Senate floor in September 2014 to explain why he was not supporting a plan to train and arm Syrian rebels against ISIS. "To those who wish unlimited intervention and boots on the ground everywhere, remember the smiling poses of politicians pontificating about so-called freedom fighters and heroes in Libya, in Syria, and in Iraq. Unaware that the so-called freedom fighters may well have been allied with kidnappers and are killers and jihadists."
Paul's reluctance to intervene overseas is not always that different a worldview from many Senate Democrats who struggled with the White House's AUMF language Wednesday, which loosely restricts armed forces from "enduring offensive ground combat operations." Many fear the language is too broad and open to interpretation to effectively stop the president from escalating the deployment of boots on the ground.
"He really is following his father's lead, skeptical of these commitments made by the United States," Sen. Dick Durbin, D-Ill., said of Paul Wednesday.
But Paul wouldn't have much to win by being seen as a Democratic ally ahead of the already-bruising 2016 primary season. Instead, he has to reconcile being consistent with the reputation he's already made for himself and simultaneously doing everything he can to carefully shed any parallels with Democrats.