WASHINGTON — Dealing a serious blow to President Donald Trump's agenda, the Senate early Friday rejected a measure to repeal parts of former President Barack Obama's health care law after a night of high suspense in the U.S. Capitol.Unable to pass even a so-called "skinny repeal," it was unclear if Senate Republicans could advance any health bill despite seven years of promises to repeal "Obamacare."A key vote to defeat the measure was cast by Sen. John McCain, R-Ariz., who returned to the Senate this week after receiving a diagnosis of brain cancer. In an impassioned speech the day he returned, McCain had called for bipartisanship on major issues of national concern, and a return to the "regular order" of legislating by committee.Three Republicans joined with all Democrats to reject the amendment, which would have repealed a mandate that most individuals get health insurance and suspended a requirement that large companies provide coverage to their employees. It would have also delayed a tax on medical devices and denied funding to Planned Parenthood for a year.The final vote was 49-51.