House Democrats, who won a majority in the midterms, plan to question the Trump administration’s decision not to defend the ACA in a Republican state AG backed lawsuit against the ACA.
In short, Republican Attorney Generals from 20 states went on what some consider to be a political witch hunt against the ACA in 2018 to try to try to get it declared illegal using Judicial power.
Then, the Trump administration added to the drama by refusing to defend the ACA in court (generally the executive branch is expected to defend federal policies).
The problem for the GOP is that the lawsuit is still stuck in the courts, but Democrats have now flipped some AG seats and taken control of the House.
Thus, while prior to the election Democrats were mostly powerless to stop the lawsuit, starting next year use their newfound power to potentially pump the breaks on it by questioning the Trump administration’s decision not to defend the federal law (as is custom) and by diminishing support by way of having Democratic AGs who flipped Republican seats not support the lawsuit.
You can read more at Reuters.com: House Democrats target DOJ decision not to defend Obamacare.