When Donald Trump came down the escalator in June of 2015 in the tower he named for himself in Manhattan, few of us who do politics for a living took his off-the-cuff announcement for president seriously.

But the past 17 months have been a lesson to all of us who flattered ourselves — as campaign pros, polling pros and media pros — that we knew more about politics than he did.

What have we learned? That Trump was being taken very seriously, indeed, by the people who ultimately mattered: voters.

Not all the voters, surely. It is not yet clear that he even won the popular vote, as counting continues in some states and Hillary Clinton might still win that metric. Much of the country woke up the day after in disbelief at the news of his election, even as financial markets were reeling from a night of selloffs around the world.

Yet Trump racked up a clear majority in the Electoral College. And he did it by winning the Anglo white vote (58 percent of it, according to the exit polls). Among people of color, he got just 21 percent. He won among men (53 percent), people older than 44 (53 percent) and people without a college degree (52 percent).

Among white people without a college degree, his share was a stunning 67 percent. The Democratic Party, which rose as the party of labor when that meant the party of the white working class, could not even compete for that vote in the critical states of Pennsylvania, Ohio, Michigan and Wisconsin. Trump won the last three by about 1 percentage point each — and with those slim margins, he claimed the presidency.

Trump narrowly lost those voters who have a college degree. But he managed to win among white college graduates by 4 percentage points, avoiding a loss with this group that would have been the first for a Republican nominee since data of this kind have been collected.

It must also be said that Trump has been elected with the worst favorable-unfavorable ratio of any major party nominee in the history of polling — consistently above 60 percent unfavorable. He kept that number up by insulting immigrants and women and NATO and Gold Star veterans' families. He did it making friendly noises toward Russian President Vladimir Putin.

But those who do like Trump, or who dislike all his rivals more, were enough to make him a winner.

It started in the primaries. In a field of 17, Trump stood out by connecting with people who previously thought of him as a TV celebrity, a real estate mogul or a casino magnate.

They knew he had no background as a politician. And they liked that about him. They knew he had little respect for the past four or five Republican candidates for president, including those who had won. And they liked that about him.

He was critical of the Iraq War begun by GOP President George W. Bush, and the trade deals negotiated by presidents of both parties over several decades. And they liked that about him.

Trump said outrageous things, insulting former prisoner of war John McCain and Fox News host Megyn Kelly, among others. He refused to commit to supporting the Republican nominee unless his own candidacy was "treated fairly." None of this seemed to bother Trump supporters nearly as much as we, the pros, said it had to.

And when a Muslim couple with ties to ISIS killed 14 people and wounded 22 more in San Bernardino on Dec. 2, 2015, many campaign pros thought Trump would fade as a candidate. After all, he had no military service and no previous office. Wrong again. Trump's candidacy took off again after he called for a temporary ban on Muslims entering the U.S.

Trump stitched together an unlikely coalition of voters to outpace 16 intraparty rivals. He did it with outreach to those not yet recovered from the 2008-09 recession, or from the loss of high-wage factory jobs. He did it by winning over evangelical Christians, abortion opponents, gun owners and ordinary people incensed at Washington and Wall Street and fearful about terrorism and immigration.

And once he had become the nominee of the Republican Party, Trump needed only to hold his base constituency and add the reluctant votes of other Republicans and compatible independents. He didn't need all those GOP officeholders who kept their distance or the big donors who looked away or the conservative opinion-makers who denounced him.

His convention in Cleveland was rocky, with high-profile rival Sen. Ted Cruz of Texas refusing to endorse him and home-state Gov. John Kasich boycotting the proceedings. In the fall, after a series of controversies about Muslims, immigrants and allegations of sexual assault, Trump stumbled through three debates with Hillary Clinton that most people thought she won.

Late in October, the Trump campaign seemed rudderless and sinking. Clinton's lead in some polls ran out to double digits. Then came a ray of hope. FBI Director James Comey announced the discovery of a new stash of emails that might be relevant to the earlier, months-long investigation of Clinton's personal email server.

Suddenly, the Democratic nominee was back at the bottom of the rain barrel. The polls moved Trump's way. Financial markets moved lower, anxious about Trump's trade antagonism — among other issues.

But in the final days before Election Day, Comey sounded an all-clear. Never mind, he said, the emails were duplicates or personal matters. The polls turned around again, the markets rose dramatically on Monday and trended higher until the close on Election Day.

So on election eve, the consensus of high-quality independent polling was that Clinton was leading nationally by 4 points. Most of us pros were expecting the suspense to be about her margin of victory. Would it be big enough to bring home a Democratic majority in the Senate? Would it be enough to give her a mandate?

Even some of Trump's surrogates and staffers seemed resigned to falling short. There was talk of how much blame to put on recalcitrant party leaders such as Speaker of the House Paul Ryan or Senate Majority Leader Mitch McConnell.

In the 7 p.m. hour, the news from Florida and North Carolina — and even Georgia — suggested that new voters, and especially Hispanics, were giving Clinton a chance to win these states. Had she done so in Florida, she would have reversed the story of the night. As it was, she was within 2 points there.

Early returns also showed Clinton prospering in Ohio, another state Trump supposedly had to win to have any chance. There was even a suggestion that Texas would not be a blowout. Texas! The idea of Clinton "expanding the map" was back in vogue, and there was renewed talk of the GOP's suicidal failure to reach out to Hispanics, women and young people.

Then suddenly Trump's numbers in Florida improved, and those in other states followed suit. Soon the focus shifted to states where Clinton was expected to win, not just compete. And here the Democrats got a shock. Trump had a lead in Virginia well into the evening (before the Northern Virginia suburbs weighed in) and he was doing well in New Hampshire.

Even more surprising trends developed in Wisconsin and Michigan, two states that had not gone Republican for president in a generation. Clinton was not reproducing President Obama's 2012 vote totals in Milwaukee and Detroit, or in other Democratic venues. Her campaign's vaunted ground game was apparently not enough to overcome a lack of enthusiasm for her among younger minority voters and the traditional Democratic rank and file.

Soon that same contagion spread to Pennsylvania, a state Trump had cultivated throughout the fall. Denied the big payoffs in Florida and elsewhere in the South, Clinton suddenly needed Wisconsin, Michigan and Pennsylvania to have a chance of 270 electoral votes. And just as suddenly, she was trailing in all three.

The rest of the night was like a bad dream for Democrats. The Senate remained securely in Republican hands, and the House added only a handful of new Democratic seats — far from the 30 takeaways Democrats needed for control.

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