Sen. Ted CruzRafael (Ted) Edward CruzWashington needs to end hidden inflation tax on our capital gains GOP tax writer introduces bill to reduce capital gains taxes Senators push to clear backlog in testing rape kits MORE (R-Texas) has surpassed Donald TrumpDonald John TrumpWSJ: Trump ignored advice to confront Putin over indictments Trump hotel charging Sean Spicer ,000 as book party venue Bernie Sanders: Trump 'so tough' on child separations but not on Putin MORE and Ben Carson in Iowa, a new poll finds, giving the Texas Republican his first lead of the cycle in an early voting state.

Cruz, who has been on a sharp upward trajectory in the polls in recent weeks, takes 24 percent of support in the Hawkeye State, according to a Monmouth University survey released on Monday.

Trump is in second place in the poll, with 19 percent, followed by Sen. Marco RubioMarco Antonio RubioHillicon Valley: Trump's Russia moves demoralize his team | Congress drops effort to block ZTE deal | Rosenstein warns of foreign influence threat | AT&T's latest 5G plans On The Money: Trump 'ready' for tariffs on all 0B in Chinese goods | Trump digs in on Fed criticism | Lawmakers drop plans to challenge Trump ZTE deal Overnight Defense: White House 'not considering' Ukraine referendum | Pompeo hopeful on plans for Putin visit | Measure to block ZTE deal dropped from defense bill MORE (R-Fla.), at 17 percent, and Ben Carson, who suffered by far the steepest decline of any candidate, clocking in at 13 percent.

Carson — who has been dogged by foreign policy blunders since last month’s terror attacks in Paris thrust national security to the forefront of the GOP campaign debates — is in free fall.

He held a commanding lead in the Monmouth survey of Iowa from late October, taking 32 percent support over Trump, who at the time was a distant second place with only 18 percent support.

Carson has fallen 19 points since then, while Cruz has gained 14 points and Rubio has picked up seven.

Evangelical voters, who make up a strong majority of Iowa caucusgoers, have moved behind Cruz, who now has a two-to-one lead over Carson among this influential bloc.

Cruz takes 30 percent support from Iowa evangelicals, followed by Trump, at 18 percent, Rubio, at 16 percent, and Carson, at 15 percent.

Last month, Carson had a two-to-one lead over Trump among evangelicals in the state, taking 36 percent support. Carson has lost 21 percent of his evangelical supporter in just over a month, according to Monmouth.

“As Ben Carson’s stock has fallen, Cruz has been able to corral most of those voters,” said Monmouth pollster Patrick Murray.

Murray noted the influence of Iowa Rep. Steve King (R), one of the foremost border-security hawks in Congress, who last month announced he is supporting Cruz for president.

About 20 percent of likely Iowa caucusgoers said King’s endorsement makes them more likely to support Cruz for president, compared to only 7 percent who said it made them less likely to support Cruz.

Thirty-five percent of those who are currently supporting Cruz for president said King’s backing makes them even more likely to do so on Election Day.

“Congressman King’s endorsement may not be the primary reason for this swing, but it certainly put a stamp on the Cruz surge in Iowa,” Murray said.

While Trump has been overtaken by a new challenger in Iowa, his support remained essentially unchanged from October.

He will be relying heavily on Independent voters who say they are likely to caucus on Feb. 1 even though they’re not registered Republicans.

Trump leads big among this group, taking 30 percent support, with Cruz a distant second, at 21 percent.

Cruz leads among Republicans who say they regularly cast ballots at the caucuses, taking 25 percent support, followed by Rubio, at 21 percent. 

“Trump will need a huge organizational effort to get independent voters to show up in a contest where they have historically participated in small numbers,” said Murray. “Without this dynamic, the underlying fundamentals appear to favor Cruz and Rubio.”

Rubio has overtaken Carson as the most popular candidate in the field, boasting a favorable rating of 70 percent, against only 16 percent who view him negatively.

Cruz and Carson are not far behind, both sitting at 67 percent favorable and 19 unfavorable. That represents a steep drop for Carson from October, when 84 percent said they had a positive view of him.

Trump sits at 54 percent positive and 36 percent negative. Sixty percent of Iowa Republicans said they’d be happy with Trump as the party’s nominee.

Rounding out the field in Iowa are former Florida Gov. Jeb Bush, at 6 percent, Sen. Rand PaulRandal (Rand) Howard PaulThe Hill's Morning Report — Trump and Congress at odds over Russia GOP leader blocks resolution backing intelligence community on Russia Rand Paul blocks Sanders's Russia resolution, calls it 'crazy hatred' against Trump MORE (R-Ky.), at 4 percent, and businesswoman Carly Fiorina and Ohio Gov. John Kasich, at 3 percent apiece. No other candidate took more than 2 percent support in the poll.

Bush’s net favorability rating is underwater at 38 percent favorable and 45 percent unfavorable.

Still, the bottom-dwellers can take solace in the fact that a strong majority of Iowa Republicans has not settled on a candidate. Only 20 percent said they have made a final decision on who they will vote for, which is essentially unchanged from the same poll in October.

The Monmouth University poll of 425 likely Republican caucusgoers was conducted between Dec. 3 and Dec. 6 and has a 4.8 percentage point margin of error.