While Congressional Republicans appear far from united on how to proceed with a plan to fully repeal and replace the Affordable Care Act, President Donald Trump wasted no time putting in place an executive order that could significantly impact existing law, potentially unraveling the entire ACA private insurance marketplace.

Trump's executive order directed federal agencies to "waive, defer, grant exemptions from, or delay the implementation of any provision or requirement" of the ACA that would "impose a fiscal burden" on states, health care providers or individuals.

The order is limited in scope, since much of the ACA can only be undone by an act of Congress. However, the directive may very well undo much of the enforcement that underpins the ACA marketplace, including of the individual mandate to purchase insurance and a variety of mandates on employers, including the requirement to provide full-time employees with coverage or pay a fine.