Washington - Senator John McCain looked like he was going to save GOP health care efforts when he returned to the Capitol earlier this week.The longtime Arizona senator had just been diagnosed with brain cancer. But he came back to the Senate in time to cast a decisive vote in favour of opening debate on GOP legislation to repeal and replace "Obamacare."Instead McCain stunned his party when the final vote was at hand early on Friday morning. He voted "no" and killed the legislation. And in the process he dealt what looks like a death blow to the Republican Party's years of promises to get rid of Barack Obama's health law.So the 80-year-old McCain was a maverick to the end - defying President Donald Trump and Senate GOP leaders.