Republicans unveiled a three-pronged strategy during the midterm elections: Repeal the bill, hold hearings to attack it and deny funding for its implementation.
"I can't imagine a Republican Congress is going to give this president the money to begin this process," Boehner said on Fox News in March, around the time President Obama signed the bill into law.
Defunding the law, however, may prove to be more difficult than Republicans envisioned. For one thing, most of the costly provisions — including the insurance subsidies that start in 2014 and the Medicaid expansion — are paid for in the law and cannot be cut without a vote to repeal them.
"It has been very difficult historically to do this type of a starving unless you have a very large majority behind you," Gail Wilensky, the top Medicare official under former President George H.W. Bush, said at a healthcare reform forum last summer. "You could technically see this as a way to go after all those things that are not mandatory funding. But a lot of the activity in this early period is, I think, not at risk."
Asked about Republicans' defunding plans, the new chairman of the appropriations health subpanel punted.
"I cannot answer how successful we're going to be," Rep. Denny Rehberg (R-Mont.) told reporters on Friday. "What we're going to do is sit down with staff and agencies to find out what is not obligated and to the best of our ability recapture as much as possible."
A likely early target is the law's Center for Medicare and Medicaid Innovation, which is tasked with testing and evaluating "innovative payment and service delivery models" and has been referred to as the "jewel in the crown" of healthcare reform by Medicare administrator Don Berwick. The law appropriates $10 billion for the center, which means funding doesn't have to be greenlighted by lawmakers.
Rehberg, however, called the funding a "slush fund" funded "without any type of direction or guidance."
"Those things need to stop," he said.
But Democrats have vowed to oppose any defunding efforts.
"Health care reform and Wall Street reform increased leverage for America's working families," House Minority Leader Nancy Pelosi (D-Calif.) wrote in USA Today last week. "Any efforts to repeal or defund them will be met with stiff resistance."
—Jason Millman contributed.