Palin, Senator John McCain's running mate pick in their failed 2008 campaign against Democrat Barack Obama, announced her support for the Republican frontrunner on Tuesday. Her endorsement comes just two weeks before voters in the Midwestern state of Iowa pick their preferred candidates in the Republican and Democratic caucuses.

"I'm proud to endorse Donald J. Trump for president," Palin said, The New York Times reported ahead of her official announcement at a campaign event.

"I am greatly honored to receive Sarah's endorsement," Trump said, according to a statement cited by The Times. "She is a friend, and a high-quality person whom I have great respect for. I am proud to have her support."

The Iowa caucuses start months of primaries preceding formal nominations in summer and November's election. Trump has emerged as the torchbearer for Republican rage as the party tries to recapture the White House after eight years of Obama.

Texas Senator Ted Cruz appeals to many of the same voters, splitting the party's far right: The sometimes-billionaire Trump has 28 percent support, just one point ahead of Cruz, according to a RealClearPolitics average of recent major Iowa polls.

In the running for the Republican nomination, Florida Senator Marco Rubio is lying third, with under 12 percent support. Onetime Iowa fronturnner and retired neurosurgeon Ben Carson has 8.7 percent. No other candidate, including establishment figures such as former Florida Governor Jeb Bush and New Jersey Governor Chris Christie, has consistently polled above 5 percent.

Actor John Wayne's daughter

Another high-profile Republican threw her support to Trump on Tuesday: Aissa Wayne, daughter of the long-dead western actor John Wayne. She said the country needed the billionaire's leadership and called him a strong and courageous leader like her father. She also said Wayne, who died in 1979, would have offered his endorsement, too.

Trump said Wayne represented the strength and power that Americans have long sought. "We have exactly the opposite from John Wayne right now in this country," he said. John Wayne was among the top box office draws for three decades, with films ranging from "Stagecoach" in 1939 through to "True Grit" in 1969.

'Big mistake'

Terry Brandstad, the Republican governor of Iowa, has not endorsed Trump, but said on Tuesday that voting for Cruz would prove a "big mistake" and alleged that the senator had sold himself out to "Big Oil."

"Everybody hates Ted," Trump told Fox News on Monday, saying that Cruz had alienated many Republicans. He followed that up on Twitter Tuesday.

The frontrunner has also alleged that the senator's being born in Canada would disqualify him from leading the United States.

On the Democratic side, establishment candidate and former Senator and Secretary of State Hillary Rodham Clinton is increasingly losing ground to a populist socialist campaign run by independent Vermont Senator Bernie Sanders.

mkg/jm (Reuters, AFP, AP)