PHILADELPHIA--Can he do it again?
Ever since Donald Trump won the 2016 election, the questions raised by that stunning result have dominated public life in America.
Had Trump exposed a fundamental shift in American politics and what voters wanted from a president? Had his nationalistic appeal been overlooked and underestimated?
Or was it just a freak event -- an unrepresentative victory by just the right number of votes in just the right states, even as Trump lost the popular vote by 3 million?
The answers are still more than a year away, but the test of Trump's staying power formally began Tuesday night, when the president launched his reelection campaign with a rally in Orlando, casting the race as a referendum on his victory and on respect for his supporters.
"This was a defining moment in American history," Trump said of his win, accusing Democrats and the news media of trying to undercut that win.
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"They tried to erase your vote, erase your legacy of the greatest campaign and the greatest election, probably, in the history of our country," Trump told 20,000 roaring supporters in a speech packed with old grievances and boasts, and little effort to lay out a second-term agenda. He cast the election mostly as a chance to reaffirm the message sent in 2016. "If you want to shut down this rigged system once and for all, then show up Nov. 3."
Another Trump win "would suggest there's enough voters out there that think the system is so broken that there's no need to try to bring (back) a sense of normalcy," said Patrick Murray, director of the Monmouth University Polling Institute.
This time, Trump starts with the power of incumbency, a muscular campaign operation that had more than $40 million in the bank at the end of March, and an economy that has steadily grown under his watch.
Yet Trump again faces significant headwinds.