Sen. John McCain (R-Ariz.) announced Friday that he would oppose the latest Obamacare repeal measure, dealing a major blow to the legislation’s prospects of getting 50 votes on the Senate floor next week. “I cannot in good conscience vote for the Graham-Cassidy proposal. I believe we could do better working together, Republicans and Democrats, and have not yet really tried," McCain said in a statement.The legislation, drafted by GOP Sens.