Transcript for Negotiators announce Senate tax plan
Next tonight, to the senate. Your money, your taxes. And it turns out senate Republicans have now revealed their tax plan that it L include a repeal of the health insurance mandate. It could save billions. But at what cost for some Americans and their insurance? ABC's Mary Bruce tonight, getting answers. Reporter: Tonight, an explosive addition to tax reform that reignites the health care debate. As part of their tax bill, senate Republicans are now aimingo repeal the Obamacare mandate that all American have insurance. Now is a good time to repeal that policy. Ive uls said, if we can get it in there, without imperilling the bill, it's a good thing. Reporter: The move solves a math problem for senate Republicans. It could save more than $300 billion over the next decade. But it's also projected to leave 13 million more Americans uninsured by 2027. Republicans have tried to get rid of the mandate before, and failed. John McCain delivering that dramatic thumb's down to the last attempt to repeal Obamacare without a replacement. Are you concerned, though, this is going to make passing tax reform even more difficult? You tried this in the past. It hasn't worked. I'm mildly concerned, but I don't think that the concerns are great enough to cause them to vote against tax reform. Reporter: But president trump wants to give this another go. Tweeting, "How about ending the unfair and highly unpopular individual mandate in Obamacare and reducing taxes even further?" Mary Bruce with us live back on the hill tonight. Mary, give us a reality check tonight. We know Republican senators can only afford to lose two votes and have this pass, so, where does the math stand tonight? Reporter: Well, David, some Republicans are already voicing concerns about this. Susan Collins, for instance, has serious questions about how this would impact premiums. But the big question tonight, will Republicans desire to pass tax reform outweigh these concerns?
This transcript has been automatically generated and may not be 100% accurate.