Donald Trump. AP In November — the sixth month of the Donald Trump phenomenon — he seemed to talk himself into the possibility.

"I'm going to win, I think," he told Business Insider in an interview then.

A little more than two months later — in the eighth month of his campaign — he is in prime position to do just that.

Beginning with an uproarious campaign launch in June, Trump has set the 2016 presidential campaign on fire, as he looks to do what most political observers once considered unthinkable: Win the Republican presidential nomination.

After more than a year of campaign bluster and posturing, Iowans will cast the first votes in the presidential-primary process on Monday. They will be followed by the voters of New Hampshire on February 9. South Carolina and Nevada come next.

The Republican side of the presidential race has been defined by the provocative, brash billionaire, who was such an afterthought a year ago that he did not register in most primary polls. He has defied years of political conventional wisdom on the way to dominating leads in those first four voting states.

Along the way, his campaign has been defined by a handful of signature moments that have proved controversial — but have only served to bolster his campaign.

'Some of them, I assume, are good people'

The announcement arrived in the inboxes of reporters on June 11, 2015.

"DONALD J. TRUMP MAJOR ANNOUNCEMENT," it blared.

Trump had flirted with presidential runs almost every cycle for the past two-plus decades. It didn't seem like a sure thing until June 16, the date of that major announcement.

He descended the escalator inside Manhattan's Trump Tower. Several minutes into a rambling speech, he finally said the words.

"So, ladies and gentlemen, I am officially running for president of the United States, and we are going to make our country great again," he said, those last five words becoming the rallying cry of his campaign.

Something he said later in his speech, though, would become a source of controversy for weeks afterward.

"When Mexico sends its people, they're not sending their best; they're not sending you," Trump said. "They're sending people that have lots of problems, and they're bringing those problems with us. They're bringing drugs. They're bringing crime. They're rapists. And some, I assume, are good people."

Democrats condemned the mogul. Businesses severed their partnerships with Trump. And much of the Republican base rallied around him.

One June 16, former Florida Gov. Jeb Bush (R) was on top of national Republican primary polls. Trump languished in the bottom half of the outsize field, registering 3.6% support in a RealClearPolitics average of recent surveys. One month later — July 19 — Trump was at 16.8%, leading the pack. He has not looked back since.

Between and thereafter, throughout the campaign, he has made illegal immigration a focal point. He pledges to deport the approximately 11 million people who immigrated to the US illegally, build a wall along border between the US and Mexico (and make Mexico pay for it), and make companies hire unemployed US workers before immigrants.

"Right now you have millions of people that are on line for years trying to come into this country. Millions of people. I don't know if you know this, but millions and millions of people are going through a process to come in legally. These people came in illegally. They're called illegal immigrants," Trump told Business Insider in November.

A January CNN poll asked Republican voters nationally which candidate they most trust to handle the issue of illegal immigration. Fifty-five percent said Trump.

Republican presidential candidate Donald Trump works a rope line after a town hall on January 29, 2016, in Nashua, New Hampshire. Getty Images

'Turning point'

On July 19, Trump took the lead in the polls. It was not expected to last for long.

That's because, the day before, he had made a statement that many political observers believed would be the end of his campaign.

"He's not a war hero," Trump Trump said of Sen. John McCain (R-Arizona) then. "He's a war hero because he was captured. I like people that weren't captured."

It was the "turning point" of the Trump campaign, said The New York Times' Nate Cohn. In what became a recurring feature of the news cycle, prominent Republican figures and his presidential rivals lashed out at Trump.

Instead, it only served to prove early on Trump's Teflon-like nature — and to illustrate how much the Republican base had soured on McCain, its 2008 nominee. The real-estate developer continued to soar upward heading toward the first Republican presidential debate.

Two weeks later came another one of those moments that, for most other candidates, would likely have served as a turning point. Trump had, during the August 6 debate, clashed with Fox News moderator Megyn Kelly, who had confronted him about his past derogatory statements about women's looks.

He was not pleased by the line of questioning. The night after, he went on CNN and made a comment that many interpreted as a crude reference to menstruation. Trump later claimed his critics were misinterpreting his remarks.

"You could see there was blood coming out of her eyes. Blood coming out of her — wherever," Trump said of Kelly's debate performance.

The deluge soon followed. Rivals blasted his comments. The influential Red State gathering of conservatives responded by demanding Trump apologize and then by rescinding his invitation from its gathering that weekend.

But Trump did not back down, choosing instead to engage in a feud with Fox News. Days later, the conflict thawed as Trump and Fox News chief Roger Ailes spoke by phone.

"I assured him that we will continue to cover this campaign with fairness & balance. We had a blunt but cordial conversation and the air has been cleared," Ailes said in a statement then.

Trump continued to fly upward thereafter. He faced challenges from retired neurosurgeon Ben Carson, who briefly overtook him in a handful of national polls, and Sen. Ted Cruz (R-Texas), who soared to eventually provide a strong contest to Trump in Iowa.

But by December 6, Trump was the top choice of more than 30% of Republican primary voters nationally. It was more than a 14-point lead on his next-closest competitor.

Donald Trump. AP Photo/Mary Altaffer

'Dog-whistle talk'

The statement landed in reporters' inboxes on December 7.

"Donald J. Trump Statement On Preventing Muslim Immigration," it read.

The Republican presidential front-runner was proposing to ban immigration and tourism to the US for Muslims.

"Until we are able to determine and understand this problem and the dangerous threat it poses, our country cannot be the victims of horrendous attacks by people that believe only in Jihad, and have no sense of reason or respect for human life," he said, his statement coming on the heels of the December 2 terror attack in San Bernardino, California, and the November attacks in Paris.

The proposal caused a distinct and pronounced backlash. By now, some rivals — like Bush, the once front-runner who had dropped more than 25 points behind Trump — were willing to make clear breaks with the mogul.

"Look, the guy's not serious. He's not a serious person," Bush said in a December interview with Business Insider. "He can't be commander-in-chief. He doesn't have plans. This is all dog-whistle talk. This is to provoke anger. This is to — with all due respect to the media — this is to generate massive attention to him. It's not about a serious plan. Is that a serious plan in all reality? Of course not."

But Trump forged ahead. Polls showed that a majority of Republican primary voters agreed with his proposal. By the end of the year, according to RealClearPolitics, he was up to 35.6% in the polls.

'I am so glad I made this ridiculous trip'

The statement landed in inboxes on January 26.

"Trump Campaign Statement on FOX News Debate," its subject read.

Trump, the Republican front-runner, announced a boycott of a debate in Iowa, four days before the Iowa caucuses, on a network that has a reputation for being the most Republican-friendly cable network.

"Unlike the very stupid, highly incompetent people running our country into the ground, Mr. Trump knows when to walk away," Trump said.

Still angry at the network and its host, Kelly, Trump would instead go on to host a fundraiser his campaign said would benefit veterans' groups.

In the days since he announced the high-profile boycott, the conversation has pervaded around whether he made the right decision or one that could cost him precious votes in Iowa on Monday.

Trump, for his part, didn't think so when he took a pseudo-victory lap in New Hampshire on Friday, declaring that Cruz got "pummeled" and that he was "glad" he wasn't there.

Tired and lacking sleep, he talked about his "ridiculous" overnight trip from Iowa to Nashua, New Hampshire. But he sounded like he was also reflecting on a long journey that looks like it'll only go on for much longer.

"I love you," he told his supporters. "I am so glad I made this ridiculous trip."