U.S. President Donald Trump spent much of the year seething as his Republican allies in Congress failed to pass legislation to repeal and replace the Affordable Care Act, as Trump had promised during his campaign. On Thursday, he took a flurry of steps that he said were meant to replace "piece by piece" what he called "a broken mess."

Democrats call his actions just the latest in a series of efforts to sabotage Obamacare, as the ACA is called. Insurers and health-care groups say Trump's moves will lead to higher costs for consumers and could potentially destabilize the marketplaces Obamacare created to serve millions of Americans. The enrollment period for next year's coverage begins Nov. 1.

1. What did Trump do Thursday?

His administration cut off a disputed subsidy to insurers that is used to help lower-income people with co-pays and other cost sharing. He also signed an executive order that tells federal agencies to consider a number of steps that to make it possible for healthy people to buy cheaper plans that provide skimpier coverage than the ACA allows. That could lead to higher costs for people who remain on regular Obamacare plans.