DES MOINES, Iowa — It was perhaps the least surprising victory in the history of the Iowa caucuses.

Donald Trump won by a landslide in the first contest in the Republican race for a presidential nominee, the margin in the end as comfortable as the polls had predicted for months.

But dominating the vote count was just one reason why the former president was celebrating on Monday night after his supporters braved extreme cold weather to deliver him the win.

Neither of Trump's main rivals, Nikki Haley nor Ron DeSantis, emerged as a lead challenger — so the not-Trump vote remains divided.

Meanwhile, his most ideologically similar rival, Vivek Ramaswamy, announced he was dropping out — and will endorse Trump in New Hampshire on Tuesday.

Here is a closer look at why the results in Iowa were so significant in the race for the White House.

Trump's victory in Iowa was historically massive. He won the most votes in all but one of Iowa's 99 counties (he lost the other by a single vote).

No one had prevailed in an Iowa contest by more than 12 points before — Trump's margin will approach 30% and he could end up winning an outright majority of the Republicans who turned out.

With almost all the votes counted, Trump had won 51%, with DeSantis on 21% and Haley on 19%.

A survey of Iowans entering caucus sites on Monday night helps explain exactly why his bid for an electoral encore has been successful so far.

About half of Republican caucus-goers consider themselves part of Trump's "Make America Great Again" movement, according to CBS News, the BBC's US partner.

Trump's victory was a broad one as well. He won the young and old, men and women. He also won over the evangelical and hard-right conservative voters he had difficulty winning in 2016.

Typically, defeated presidential candidates fade from memory, never able to shake the taint of the loss. Trump, however, has managed to convince Republicans — here in Iowa and nationally — that he didn't lose.

A large majority of caucus-goers in Iowa told CBS they believed Trump was the actual winner of the 2020 presidential election — a number that increased to 90% among Trump supporters.

Trump's dominant position within the Republican Party has been irrefutable — but his win here, in the larger context of modern American politics, is extraordinary.

Three years ago, he ended his first presidential term under a cloud of controversy, his campaign to challenge his loss to Democrat Joe Biden culminating in the Jan. 6 Capitol riot. He faces two criminal trials stemming from those actions.

Now, as the winner of the Iowa caucuses, he has taken the first significant step toward becoming the Republican Party's nominee in November's presidential election.

Trump still has work to do to become the Republican standard-bearer. He will face a more formidable challenge from Haley in New Hampshire next week, where polls show his once dominating lead has been whittled to near single digits.

But he is still the overwhelming favorite in the race, endorsed in his first test by actual Republican voters.

Entering Monday's Iowa caucuses, most of the electoral intrigue involved which candidate would take second place behind Trump. In the end, it was DeSantis who walked away with the runner-up prize.

It's not much of an achievement, however, given the narrowness with which the Florida governor finished ahead of Haley, after investing so much time and resources in Iowa.

The result, and DeSantis's pledge to press on with his campaign, won't provide the kind of clear result that would set up a one-on-one face-off with Trump in the days ahead.

In fact, the result may make Trump's victory all the more potent, as his divide-and-conquer strategy is still fully in place as the Republican primary process kicks into gear.

The one candidate who did drop out, Ramaswamy, will further clear the field for the former president, as public opinion surveys show that his supporters have Trump as their second choice.

While he only garnered about 8% in Iowa, every bit of backing counts, and Ramaswamy's endorsement will offer Trump yet another headline to boost him into New Hampshire.

The Iowa result will also let the former president further focus his fire on President Biden, something he eagerly did during his victory speech on Monday night. For their part, the Democrats seem to be welcoming the showdown and the opportunity to exploit what they see as Trump's vulnerabilities.

A series of dominating wins, starting in Iowa, will give the former president momentum, however — and the air of a winner. By the time the autumn general election rolls around, Trump may prove to be a more formidable adversary than they expected — or hoped. — BBC