Congress enacted the Children’s Health Insurance Program in 1997 as a more modest and more bipartisan expansion of federally funded insurance than compared with the failed bid of Bill and Hillary Clinton for universal health care in 1994. George W. Bush vetoed efforts to increase the program’s reach, but Democrats succeeded in expanding it once Barack Obama took office in 2009 and again as part of the Affordable Care Act a year later. The Obama administration and Republican congressional leaders struck a deal in 2015 to reauthorize the program, which by then had been credited with helping reduce the uninsured rate among children from nearly 14 percent two decades ago to under 4.5 percent.

As with so many long-standing policies, Donald Trump’s election in November threw CHIP’s future into question. Would Republicans now fully in charge of the government maintain their support for a program associated with Trump’s opponent at the same time as they tried to dismantle the Affordable Care Act? Noting that there was now “uncertainty about other sources of coverage,” the Medicaid and CHIP Payment and Access Commission pressed lawmakers in January to extend the program’s funding for another five years. “At this time, the urgency of congressional action to preserve health-insurance coverage for the nation’s low- and moderate-income families cannot be overstated,” wrote the commission’s chairwoman, Sara Rosenbaum.

So far, however, Congress has done nothing aside from scheduling its now-cancelled hearing. Advocates were hopeful that once the House initially failed to pass the GOP health-care bill in March, it would create an opening to reauthorize CHIP. But now that the Senate is taking up its own Obamacare repeal bill, “all bets are off,” Lesley said.

It often takes a deadline for Congress to act, and there’s little concern yet that the House and Senate will let CHIP’s federal funding lapse entirely. But the program’s advocates say lawmakers must move by this summer or as many as 1.1 million families will receive letters warning them that their insurance policies could end. Millions more would not necessarily lose coverage immediately but could face higher costs if federal support for the program runs out. “The closer we get to the deadline, the more havoc it wreaks,” said Lisa Shapiro, vice president of First Focus. Families “start feeling like [CHIP] is not an option for them any longer. And it’s hard to get those families back once they think the program is up in the air for their kids and is not going to be there for them any longer.” Adding to the legislative headache is the litany of other urgent deadlines Congress will face in September, when lawmakers are likely to confront both a possible government shutdown and a must-pass increase in the debt ceiling.

Some states operate CHIP through Medicaid, while others run it as a separate program. The GOP’s health-care bill does not directly affect CHIP, but its more than $800 billion in cuts to Medicaid could force more families to turn to CHIP and raise the cost of the program to the federal government. And that uncertainty will make it difficult for Congress to determine its funding before it settles the question of Obamacare. “We’d like a bipartisan CHIP extension, but we don’t even know what world we’re going to be living in when and if we get to that stage,” a Democratic congressional aide told me.