Critics say Idaho's insurance department can't unilaterally ignore federal law, including some of the Affordable Care Act's protections for people with pre-existing conditions. Otto Kitsinger/AP hide caption

A sign in support of Oregon's Measure 101 is displayed by a homeowner along a roadside in Lake Oswego, Ore. Tuesday's special election puts decisions over how the state funds Medicaid in voters' hands. Gillian Flaccus/AP hide caption

Demonstrators protest at Sen. Dean Heller's, R-Nev., office in support of the Deferred Action for Childhood Arrivals (DACA), and Temporary Protected Status (TPS), programs on Capitol Hill on Tuesday. Jose Luis Magana/AP hide caption

Up to one half of rural residents are covered by Medicaid, says Michelle Mills, CEO of Colorado Rural Health Center. And they're typically older, poorer and sicker than city dwellers. John Daley/CPR hide caption

The CHIP program provides health coverage to 9 million children from lower-income households that make too much money to qualify for Medicaid. The $2.85 billion Congress allocated in December was supposed to fund CHIP programs in all states through March 31. But federal health officials say it won't stretch that far. Karl Tapales/Getty Images hide caption

Each year, hundreds of hospitals lose 1 percent of their Medicare payments through the Hospital-Acquired Conditions Reduction Program. The penalties — now in their fourth year — were created by the Affordable Care Act to drive hospitals to improve the quality of their care. Maskot/Getty Images hide caption

Kelley Mui helps a client sign up for health insurance through the Affordable Care Act on Dec. 15 at the Midwest Asian Health Association in Chicago. Scott Olson/Getty Images hide caption

Some Republicans see HSAs as a great way of helping consumers deal with mounting medical costs. It's still possible a change to the rules governing who can have an HSA and what they are allowed to cover could be added to another bill, some analysts say. Gary Waters/Ikon Images/Getty Images hide caption

The homepage of the Affordable Care Act exchange on Nov. 1, 2017 in Miami. The open enrollment period to sign up for a health plan on HealthCare.gov runs through Dec. 15; several states with their own health care exchanges have later deadlines. Joe Raedle/Getty Images hide caption

Isabel Diaz Tinoco and Jose Luis Tinoco had some questions for the Miami insurance agent who helped guide them in signing up for a HealthCare.gov policy at the Mall of the Americas in November. Joe Raedle/Getty Images hide caption

Opposition to Obamacare has been strong from the beginning. Demonstrators made their dissatisfaction clear in front of the Supreme Court in 2015. Mandel Ngan/AFP/Getty Images hide caption

A week after Hurricane Harvey swept through southern Texas in August, the streets of Katy, Texas, were still flooded. People in Puerto Rico and the Southeastern U.S. who were affected by the hurricanes are among those who may have extra time to enroll for 2018 health plans. Justin Sullivan/Getty Images hide caption

Sen. Susan Collins, a Republican from Maine, walks through the Capitol with colleagues in early December. Aaron P. Bernstein/Bloomberg via Getty Images hide caption