Sarah Palin’s endorsement seemed to have done the trick.
Florida Senator Marco Rubio is in third place at 14 percent, and neurosurgeon Ben Carson at 6 percent.
Winning Iowa is widely considered to be Cruz’s only chance to win the Republican nomination. Trump has an overwhelming lead over Cruz in the other key early primary states of New Hampshire and Florida.
In Florida, Trump leads the field with the support of 48 percent of GOP voters, with Cruz a distant second at 16 percent, according to a recent poll by Florida Atlantic University.
Cruz is considered the strongest GOP challenger to Trump, after polls showed him having a slight lead over Trump in Iowa in December, according to RealClearPolitics averages, but he’s now fallen to second place.
Cruz is the latest challenger to have temporarily peaked over Trump in Iowa. In October, Ben Carson polled better than Trumps for a few weeks before falling back in polls eventually sliding to his current spot in fourth.
In addition to Palin, Trump has also racked up endorsements from grassroots conservative stalwarts like Phyllis Schlafly, who praised Trump effusively in a lengthy interview with Breitbart earlier this month. Schlafly has been a prominent conservative activist and writer since the 1964 elections, when she supported Barry Goldwater.
The Iowa caucuses open on February 1st.