Transcript for McCain says he will vote 'no' on the latest attempt to kill Obamacare
The major headline, a major blow in the new effort to kill Obamacare and it comes from the same senator who killed the repeal the last time. Senator John McCain declaring he will vote know. The two key senators who will break or make this repeal. Where do they stand tonight. Reporter: It's been just eight weeks since the country watched John McCain walk onto the senate floor, shocking his own party, with this defiant thumbs down. Reporter: His vote delivering the final blow to the president's attempt to repeal and replace Obamacare. Tonight, with one more chance at a repeal before next week's deadline, John McCain stunning the party again. Announcing today, "I cannot in good conscience vote for" the latest Republican plan. He says a "Bill of this impact requires a bipartisan approach." McCain might have just killed this new repeal, because they can only afford to lose two votes. Rand Paul has already said no. And McCain did this, even though his own best friend in the senate, Lindsey graham is one of the architects. I don't expect him to vote because we're friends, I expect him to vote for what's best for the country. Reporter: The bill would give states more flexibility to craft their own health coverage, but with far less federal funding. And with no guarantee of how they would cover Americans with pre existing conditions. Experts say it could leave millions more without insurance. All eyes now on two key senators. Senator Susan Collins of Maine, and Lisa murkowski of Alaska. Collins tonight is leaning no. I just have to do what's right of the people of Maine and our country, and if I don't do that I can't look at myself in the mirror. Reporter: And senator Lisa murkowskis office protesters camped out urging her to protest this bill like she did the last time. I said in January we should not repeal without a replacement. Just an indefinite hold on this just creates more chaos and confusion. Mary Bruce back with us from Washington. And Jimmy Kimmel whose own baby needs several operations, and fought for other families to have coverage if they're in the same situation. He tweeted senator McCain. Reporter: Yeah. Kimmel with a tweet of praise saying thank you John McCain for being a hero again and again and now again. And John McCain's wife responded tweeting thank you for the kind words about my hundreds and god bless your sweet baby. David. As we head into the weekend,
This transcript has been automatically generated and may not be 100% accurate.