But the problem they all face in making their case to skeptical lawmakers is that the exact mechanism for default isn't clear, even to them.
Asked directly how it would happen, Chairman of the Council of Economic Advisers Jason Furman acknowledged that failure to raise the debt limit wouldn't cause the U.S. to instantly fall off the proverbial cliff.
"We've never actually tested it," Furman said Monday. "We don't know what happens. And we don't ever want to find out what happens."
Some lawmakers, like Rep. Ted Yoho, R-Fla., have pledged that they won't vote to raise the debt limit at all, and others have said they'll only do it if the vote is accompanied by reforms that reduce the country's debt overall.
Either way, come Oct. 17, the Treasury Department says that unless Congress acts, on that day it will run out of "extraordinary" measures they've utilized for the last several months to pay the country's debt.
But a few Republicans view even that date as an arbitrary timeline used by the White House to gain leverage and kick long-term budget reforms down the road.
By Rep. Tim Huelskamp's calculations, we have "about five weeks" until the Treasury department faces a sizable enough payment that it might require it to raise the debt ceiling.
"I think the Oct. 17 date … is not the real date," the Kansas Republican told ABC News. "We don't have a payment on debt until Oct. 31 according to the Treasury Department…we have a big one on Nov. 15."
"It's in their interest to kind of keep fudging with those numbers and moving them up to create pressure," he added.