Democratic leaders will have to navigate alongside a caucus of moderates who back strong military spending and progressive members who have decried Pentagon largess.
The report from the Government Accountability Office is likely to add to Democrats' election-year narrative that the administration actively undermined "Obamacare" without regard for the consequences to consumers.
Democratic Rep. Frank Pallone of New Jersey, who filed a complaint last year, called the tweet "another example of the Trump administration's illegal and unacceptable use of taxpayer funds for political gain."
The proposed regulation from the Labor Department would provide more health insurance options for self-employed people and small businesses, but its success depends on buy-in from insurers, state regulators, plan sponsors and consumers themselves. Some groups already have concerns.