New Congress, all-GOP, same political divisions
The House Freedom Caucus consists of about 30 of the most conservative members, many of whom were elected in the tea party wave of 2010 that surged in opposition to Obama's Affordable Care Act.
Some conservatives, including the Freedom Caucus, say the bill looks too much like Obama's health law, with the federal government mandating the kinds of coverage that insurance companies must provide.
If the Freedom Caucus falls in line, they can help hand Trump a major victory on health care, boosting the president's standing to take on other tough issues.
The measure would repeal major parts of Obama's health law, capping future funding for Medicaid and cutting tax increases for high-income families, health insurance companies and drug makers.
The bill repeals tax credits that people can use to purchase health insurance and replaces them with a new tax credit that is less generous for most.