That Republicans might extend CHIP is a testament to its popularity. After 18 years on the books, the program is an accepted component of the social safety net. Health policy experts say it has succeeded in its original goal of providing coverage to more than half of the nation’s uninsured children. And when congressional leaders asked governors last year what to do with the program, both Republican and Democratic state leaders urged them to continue it, said Ron Pollack, the executive director of FamiliesUSA. CHIP’s trajectory is a mark of hope for supporters of Obamacare—and a reason for fear among conservatives. The longer a government program endures, the more popular it becomes, and the harder it is to eliminate it.

Still, there’s a crucial difference between CHIP and the Affordable Care Act, aside from the much broader scope of the 2010 overhaul. “The Children’s Health Insurance Program has, from its origination, been a bipartisan program,” Pollack noted. In Congress, it was the brainchild of the late Senator Ted Kennedy and Senator Orrin Hatch, a Republican of Utah who now heads the Finance Committee. Hillary Clinton, just three years removed from her failed bid to shepherd universal health care into law, championed the more limited insurance expansion from the White House. It was ultimately included in a larger budget deal that Republicans passed and President Clinton signed in 1997. A decade later, Hillary Clinton drew some criticism for embellishing her role in the program’s passage, given that she stayed mostly behind the scenes after stumbling on health care earlier in her husband’s tenure. “Success has more than one set of parents in the political arena,” Pollack said. “Clearly, she played a significant role.”