This single vote could very well be John McCain's legacy. In one vote he got even with Obama, and now we could have MCCAINcare. And has a anti-Trumpist he gave it to Trump. So in typical McCain style McCain comes first and the country a distant second.
Democrats want the mandates, as a mean of control, and Republican want We the People to be in control of their health care needs. This all come down to trust, Republican trust We the people, to be able to make their own decision, and Democrat don't, and McCain wants everyone to look at him.