Republicans do not need Democratic votes to repeal the core of the law through the special process known as reconciliation, which allows the measure to advance with a simple majority in the Senate.
Powerless against a reconciliation bill, Democrats are trying to gin up political pressure to try and stop the Republican push.
Democratic leaders have organized rallies against repeal for Jan. 15, and pro-ObamaCare groups have launched ads in states with Republican senators that they think are most likely to be swayed. Those states include Arizona and Nevada, home to the two 2018 Senate races where Democrats are seen as having some chance of picking up a seat.
Democrats argue that Republicans should not repeal the law, even on a delay, and jeopardize healthcare for more than 20 million people until they have put forward a replacement plan.
Secretary of Health and Human Services Sylvia Burwell met with congressional Democrats on repeal earlier this month.
She distributed materials about the HHS “Coverage Matters” campaign, which features stories from ObamaCare enrollees, as well as a study from the Urban Institute showing that about 30 million people would lose coverage under repeal.