Senator Ted Cruz, sounding every bit the pastor's son, came to the pulpit in a spirited mood Monday night.

Before him stood his Republican faithful, a congregation of conservative Iowans basking in his caucus victory at the state fairgrounds in east Des Moines.

Reciting a passage from Psalms, the Texas senator brought to mind the soaring, theatrical delivery of a televangelist: "Weeping may endure for a night," he said. "But joy cometh in the morning."

They were prophetic words. Following Monday night's first-in-the-nation Iowa caucuses, it is indeed a new day in American politics, with the Washington establishment waking up sore.

In the Republican contest, Cruz — the proud Washington "outsider" despised by Senate colleagues — defied polls by besting the perceived frontrunner Donald Trump.

Cruz finished with 27.6 per cent to Trump's 24.3 per cent. Marco Rubio finished a close third with 23.1 per cent of the vote.

In the Democratic race, Vermont Senator Bernie Sanders fought formerly presumptive nominee Hillary Clinton virtually to a draw. (The final result gave Clinton 49.8 per cent of the vote and Sanders 49.6 per cent.)

That may have been good enough for Sanders, however, as he goes to the next stage with a lead in New Hampshire polls.

Ted Cruz supporter Debbie Levey

Ted Cruz supporter Debbie Levey, 53, celebrates the Texas senator's victory in the Republican Iowa caucus on Monday night at the Iowa state fairgrounds in Des Moines. (Matt Kwong/CBC)

"It looks like we are in a virtual tie," he told supporters Monday night, before being drowned out by cheers and breaking into laughter.

Clinton declared a win at her prematurely named "Caucus Night Victory Party," saying she was "breathing a sigh of relief."

So long as she can limp out of Iowa without a loss, political observers say, Clinton should be in good shape for winning support from states with more diverse demographics.

Even so, caucus-goers in the Hawkeye State seemed to be communicating frustrations with "politics as usual," said Don Kass, the Republican chairman for Plymouth County in Iowa.

Ted Cruz supporter Donnie Kline

Ted Cruz supporter Donnie Kline wears a button endorsing the Texas senator for next president of the United States in 2016. (Matt Kwong/CBC)

"Frankly, for both parties, this looks like a message to the Washington establishment," Kass said.

"When you've even got Hillary and Bernie running neck-and-neck, it's like saying the anti-establishment types are saying you'd better start listening to regular people."

The Iowa caucuses are as much about who gets eliminated as about who wins.

Caucus outcomes highlight strengths, expose weaknesses and winnow contenders down to the most compelling — or at least the loudest — voices in the race for the presidency.

"Trump's second-place showing deflates his balloon. He just does not look as inevitable tonight as he did this morning," said longtime Des Moines Register political columnist David Yepsen.

Republican caucus goers

Republican caucus goers sit in the auditorium of Park Avenue Elementary school in south Des Moines on Monday night. Across the hall in the library of the school, a Democratic caucus was underway at the same time. (Matt Kwong/CBC)

University of Virginia political analyst Kyle Kondik points to Trump's lack of a traditional retail politics campaign of grassroots door knocking in Iowa as his downfall. For all his crowd sizes, his support base also indicated low propensity to actually show up to caucus.

'It would take a miracle for some of these bottom finishers to resurrect themselves in New Hampshire.' - Columnist David Yepsen

"It also may be that he's truly more of a novel candidate than a real candidate," Kondik said.

Campaign casualties on Monday night included Republican Mike Huckabee and Martin O'Malley, the Democratic former governor of Maryland, also suspended his nomination bid.

"It would take a miracle for some of these bottom finishers to resurrect themselves in New Hampshire," Yepsen said. "At the same time, there's a clear delineation of three top finishers that will get to move on."

A candidate's failure to crack the top three in either party usually snuffs out dreams of moving in to the White House. Only once in 15 Iowa caucus cycles has there been an exception.

Strong 3rd place

What this means, Yepsen said, is that Iowa's conventional wisdom that whoever carries Iowa carries the momentum, and that the adage that there are "three tickets out of Iowa" will again prove correct.

Rubio, who achieved a strong third-place showing, was one of the surprises of the night, and emerged as a new hope for a bruised Republican establishment. The Florida senator might be the man who party leaders can look upon as an alternative to Cruz's uncompromising style and a way out of furthering Congressional gridlock.

Those deep fissures between Democrats and Republicans became more obvious during caucus voting on Monday night in south Des Moines. At Park Avenue Elementary School, Democrats caucused in the library while Republicans occupied an auditorium down the hallway.

The library was the scene of chaotic, frenzied movement, with chants of "Feel the Bern!" and a sense of playfulness. Neighbours beckoned the room's four O'Malley supporters to sit with the Clinton camps or stand in a corner with Sanders supporters after O'Malley was declared "not viable" in the precinct. Linda Poil, untethered from O'Malley, was cheered and hugged when she dragged her chair over to sit with Clinton caucus voters.

'You should speak English'

In the Republican auditorium, caucus goers sat quietly in pews and voted for candidates by secret ballot. When asked to raise political issues of concern for the party platform, Rachel Gudiel stood and denounced the lack of assimilation from new immigrants.

"When you come to America, you should speak English," she said.

Sitting in a back row, Cruz supporter John Notch raised his hand and told of his frustration with constitutional carry restrictions, expressing concern about the erosion of the right to bear arms and his wish for citizens in all 50 states to be able to arm themselves openly or concealed.

"I believe that's our constitutional right, and the reciprocating laws around the United States are very confusing," he said.

This year's Iowa caucus reportedly brought a record voter turnout, with 180,000 Republican Iowans voting, compared with a previous record of 121,000 in 2012.