The latest U.S. political survey shows billionaire real estate mogul Donald Trump and staunch conservative Texas Senator Ted Cruz in a virtual dead heat in the farm state of Iowa, days ahead of the first voting in the race for the 2016 Republican presidential nomination.
In polling in recent days, Quinnipiac University said the flamboyant Trump won support of 31 percent of Republican voters likely to participate in next Monday's caucuses in Iowa, compared to 29 percent for Cruz.
National surveys, however, show Trump, a long-time New York developer, casino magnate and television reality show host, with a commanding lead over Cruz and another 10 candidates even further back in the contest to be the Republican nominee in the November national presidential election.
Quinnipiac polling official Peter Brown said that even as Trump and Cruz have traded political barbs in recent days, "the Iowa Republican caucus remains too close to call. One week before the caucuses gather, the question is which candidate has the best field organization.If the events of the last two weeks haven't moved the needle, one wonders what would change it in the next six days.
"It all comes down to turnout. And with four in 10 likely caucus participants saying they still might change their mind, this is an especially volatile race," Brown added.
Cruz has emphasized the importance of next Monday's first-in-the nation voting in Iowa, even though it is just the initial balloting in what will be a lengthy state-by-state series of contests to pick a Republican nominee at a national party convention in July.
Cruz told a group of Iowa religious leaders that Trump "could be unstoppable" if he wins in Iowa. Surveys show Trump far ahead of the field in the northeastern state of New Hampshire, the next state set to vote after Iowa, on February 9, and leading in other states as well.
A new national CNN/ORC poll showed Trump with 41 percent support among Republicans, more than double the 19 percent support registered for Cruz, who led a 16-day partial shutdown of the national government in 2013 in a futile effort to overturn President Barack Obama's health care reforms.
CNN's new polling was the first time the news organization showed Trump with more than 40 percent, and more than two-thirds of Republicans said they believe that eventually he will be the party's presidential nominee.
A new national Fox News poll showed former secretary of state Hillary Clinton still ahead in the race for the Democratic presidential nomination, but with her lead dwindling over Vermont Senator Bernie Sanders, who identifies himself as an independent Democratic socialist.
The Fox poll showed Clinton ahead by 49 to 37 percent over Sanders, down from a 15-point lead two weeks ago.
Polls in Iowa show the two Democrats running neck-and-neck, while Sanders holds a commanding lead in New Hampshire, which adjoins his home state.
The winner of the November national election will replace Obama as he leaves office a year from now.