For weeks, Iowa Republican insiders have noted that Texas Sen. Ted Cruz was rising fast in the state that holds the first voting in the 2016 presidential race.

Now, he may have broken through.

Cruz, a favorite of tea-party activists and evangelical Christians, sits in first place in a new Monmouth University Poll released Monday of likely Iowa GOP caucus-goers, dethroning past leaders Ben Carson and Donald J. Trump.

The poll finds Cruz the first choice of 24 percent of likely caucus attendees, to 19 percent for Trump, 17 percent for Florida Sen. Marco Rubio and then Carson, a retired neurosurgeon, at 13 percent. Jeb Bush stands at 6 percent and Kentucky Sen. Paul is at 4 percent. Carly Fironia and John Kasich each earn 3 percent support. None of the other six candidates tested draws more than 2 percent support.

Monmouth's Iowa poll two months ago showed Carson on top, but his support has since dropped by 19 percentage points as voters began to express doubts about his mastery of foreign policy and national security issues amid heightened concern over terrorism. Cruz's support has jumped by 14 percentage points, and Rubio gained 7 points in Iowa vote share.

"This marks the first time Ted Cruz has held a lead in any of the crucial early states.  As Ben Carson's stock has fallen, Cruz has been able to corral most of those voters," said Patrick Murray, director of the independent Monmouth University Polling Institute in West Long Branch, N.J.

Evangelical voters, about half of the Iowa GOP caucus electorate, back Cruz (30 percent) over Trump (18), Rubio (16), and Carson (15) in the new Monmouth survey.  In October's poll, Carson held the advantage with this group – garnering 36 percent support to 18 percent for Trump, 12 percent for Cruz and 9 percent for Rubio.

The Monmouth poll was conducted from December 3-6 with 425 likely Republican caucusgoers and carries a margin of error of plus-or-minus 4.8 percentage points.