Politically, the big unknown is whether or not Paul Ryan and Mitch McConnell will get away with trying to pin the blame for this on the Democrats/the law itself. That's why they've been pushing the "Obamacare is already in a death spiral!" claim hard for the past few weeks, even though it quite simply isn't.
...So, if this does end up in a worst-case scenario, Trump's "stop enforcing the mandate altogether!" order here could end up causing that death spiral even if the GOP doesn't technically end up repealing anything legislatively. The carriers would start announcing that they're bailing next year as soon as this spring (remember, the first paperwork for 2018 exchange participation has to be filed in April or May), and McConnell/Ryan would simply say, "See?? We told you it was collapsing all by itself! We didn't touch nuthin'!!"
The Trump administration apparently was unable to scrap all outreach efforts to enroll individuals in Obamacare, following widespread concern that its move Thursday to pull ads promoting enrollment could destabilize the insurance marketplace.
The Trump administration has pulled the plug on all Obamacare outreach and advertising in the crucial final days of the 2017 enrollment season, according to sources at Health and Human Services and on Capitol Hill.
Even ads that had already been placed and paid for have been pulled, the sources told POLITICO.
...Individuals may still sign up for Obamacare plans until the Jan. 31 deadline — but the Trump administration isn't advertising that fact any longer.
It is also halting all media outreach designed to spur signups in the days leading up to the deadline. Emails are no longer being sent out to individuals who visited HealthCare.gov, the enrollment website, to encourage them to finish signing up. Those emails had proven highly successful in getting stragglers to complete enrollment before the deadline.