Rick Hampson

USA TODAY

NEW YORK — He rode down an escalator into the glittering lobby of a Fifth Avenue skyscraper he’d built himself. She stepped up to a stage on an island in the East River named for one of her political heroes.

That was June 2015, when Donald Trump and Hillary Clinton launched their presidential campaigns in earnest three days and one mile apart. At the time, the proximity didn’t seem important; the candidacies didn’t seem equivalent.

She was an inevitability, already the assumed standard-bearer for Democrats heading into the 2016 campaign. He was an impossibility — just one more entry, the 12th, in a still-growing Republican field. He was expected to contribute little more than reality TV-style entertainment. When his GOP rivals talked about Trump, they smiled.

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But now, with Election Day a week off, it’s clear that first week contained clues about why neither campaign would go as expected; why Clinton’s juggernaut would be slowed by Bernie Sanders, yet ultimately prevail; why Trump would rout his competition, including nine past or present governors and five past or present U.S. senators.

Saturday, June 13, was Clinton's first big rally, held on Roosevelt Island at a park also named for Franklin D. Roosevelt, who in the war year of 1941 enunciated “four freedoms’’ he said people everywhere deserved: Freedom from want and fear, and freedom of speech and worship.

Clinton promised “four fights,’’ none as readily memorable as FDR’s freedoms: to create a fairer economy, to strengthen families, to maintain America’s world leadership and to reform government.

She did not mention Trump, his treatment of women or his taxes. She called herself a “fighter,’’ unaware her eventual opponent would be one of the biggest brawlers in the history of U.S. politics.

Trump announced the following Tuesday at Trump Tower. He said many undocumented immigrants from Mexico were criminals and rapists; promised to force Mexico to pay for a giant wall he’d build along the Southern border; complained that Americans “don’t have victories anymore,’’ especially in trade negotiations.

He vowed “to make our country great again.’’

He did not mention Hillary Clinton, her emails or the Clinton Foundation.

After their announcements, the candidates flew to Iowa to campaign. In reality, they’d been candidates for months; Trump had formed an exploratory committee in March, and Clinton formally announced in April, albeit via online video.

But it was in mid-June, nearly 17 months before Election Day, that 2016’s beast of a general election began to stir. Looking back, there was much that week told us, not about what was too come, but about how the candidates and their campaigns would handle it when it did.

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He’d stick to a few themes — simple, memorable, visceral.

That first week it was jobs, immigration and trade. The menu would change over the months to include other items — crime, election fraud, his opponent’s dishonesty. The constant was Trump's ability to tap into voters’ emotions and probe his rivals’ weaknesses.

He didn’t give a lot of details. He said “believe me’’ a lot. And by the end of the month, he’d trail only Jeb Bush in a poll of New Hampshire primary voters.

She’d be cautious, deliberate, detailed.

The Roosevelt Island speech contained a litany of liberal to moderate ideals that appealed to almost every Democratic constituency. Each word seemed focus-group-tested and committee-vetted.

Later in the week came specifics. In New Hampshire, she called for universal prekindergarten for every 4-year-old within a decade. In South Carolina, she proposed a $1,500 tax credit for certain businesses that hire apprentices.

Asked in an Iowa radio interview about President Obama’s plan to send 450 military advisers to Iraq to combat the Islamic State, she spoke slowly and carefully:

“I do not believe that U.S. troops should be on the ground in Iraq doing combat. I think what the president is trying to accomplish is using the unique skills that the American military has in intelligence, surveillance, training, to buttress the efforts of the Iraqis themselves. I have supported the president's approach to dealing with this very serious treat.’’

Trump on the same topic: "We should go blast the hell out of that oil."

He’d be unscripted.

Trump had no text, no teleprompter, no filter. He was spontaneous, occasionally rambling, always entertaining. He was immodest — “I’m really rich,’’ he said — and shamelessly plugged his hotels and golf courses.

“I like going off script,’’ he said after his announcement. But he seemed to have it in his head.

He’d live (or die) with social media, free TV and a bare-bones organization.

Trump, the organizational genius who said he “built a great, great business,’’ didn’t have much of a political organization.

He didn’t seem to think he needed one. Not with 3 million Twitter followers and 1.7 million Facebook fans at the time. In the 24 hours after he announced, 3.4 million Facebook users shared information about Trump 6.4 million times. When Bush announced that Monday, the comparables were 493,000 users and 849,000 messages.

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She’d bend, but not break.

Clinton’s flexibility was on view that week on trade — one of the few issues that united Trump and Sanders, but that she handled bloodlessly in her kickoff speech: Global trade had “created whole new areas of economic activity and opened new markets for our exports, but … also displaced jobs and undercut wages for millions of Americans.’’

She recovered the next day, signaling she was easing away from her original support for the increasingly unpopular Trans-Pacific Partnership trade pact and urging Obama to confer with House Minority Leader Nancy Pelosi (a TPP opponent) “to make sure we get the best, strongest deal possible, and if we don't get it, there should be no deal.’’

By October, she'd withdrawn her support for the agreement entirely.

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He’d attack, attack, attack.

Just ask Neil Young.

After the rock star objected to Trump’s use of his song Rockin' in the Free World at the Trump Tower announcement — Young supported Sanders — Trump took to Twitter to call Young a "total hypocrite" who once visited Trump's office requesting money for an audio deal.

Trump also had words for Bush’s open-collared presidential announcement: “He can't even put on a tie and jacket. He's running for president. Maybe he knows something I don't know. Maybe I should take it off because I want to be one of everybody. You know what? You run for president, maybe put on a tie."

She’d play the gender card.

In 2008, Clinton sometimes seemed to downplay her gender. This time she embraced it. On Roosevelt Island, she joked that while she might not be the youngest person ever elected president, she’d be the youngest woman.

Trump took note. “She's playing the woman card really big,’’ he told a crowd in Des Moines the night he announced. “I watched her the other day and all she would talk about was, 'Women! Women! I'm a woman! I'm going to be the youngest woman in the White House!’’’

In New Hampshire, she helped read The Very Hungry Caterpillar to a pre-K class — something it was hard to imagine Trump doing. Later in the campaign, at a rally, he’d make fun of a crying baby.

He’d run as a conservative without conservative consensus.

Karl Rove, George Will, the Koch brothers — none from the start had any use for Trump, who seemed reluctant to touch social welfare entitlements and prone to presidential overreach.

"Trump is so far from being a mainstream Reagan-style conservative that the real question is why he is bringing his circus to the GOP tent in the first place,'' wrote Jeff Jacoby, a conservative columnist for The Boston Globe. Trump's announcement speech, he said, "drove the needle on the crazy-meter way into the red zone."

She could get under his skin.

After a gunman killed nine members of a Bible study group in Charleston, S.C., on the Wednesday after the campaign kickoff events, Clinton said that Trump’s comments about Mexicans were the kind that could "trigger people who are less than stable to do something. … Everybody should stand up and say that's not acceptable."

Trump took the bait, accusing Clinton in an Instagram video of a “pathetic’’ attempt to blame him for the tragedy. He said it was more proof that "politicians are just no good."

He wouldn’t back down.

After the Trump Tower speech, as sponsors severed their connections to him and denunciation rained down across the political spectrum, Trump was offered a chance to back off.

Many candidates would have; not him. “The speech went well,’’ he told the Associated Press. “There's nothing in there I didn't mean."