Predictions that Donald Trump would not be able to hold on to his front-runner status have failed to materialize days before the Iowa caucuses, but most Americans say they nevertheless are uncomfortable with the idea of the real-estate tycoon moving into the White House.

In a poll conducted by the Washington Post and ABC News, 69 percent of respondents say the prospect of a "President Trump" made them anxious, suggesting that Trump would face an uphill battle in the general election if Republicans were to crown him their nominee, the newspaper reported. Only 3-in-10 Americans have no worries about the former "Apprentice" star running the country.

Author: Trump 'lacks connections' to traditional politics

Historian Rick Perlstein, the author of the 2014 bestseller "The Invisible Bridge: The Fall of Nixon and the Rise of Reagan," meanwhile, told Slate that voters were right to fear a Trump presidency.

"Donald Trump is perhaps most interesting in his lack of connections to (the traditional political) world," Perlstein noted. "The first sign that something very different was happening was when he basically rejected Fox News, threw them over the side, and had no interest in kowtowing to them."

Trump's surprisingly tense relationship with the news channel, of course, was on display this week as the GOP front-runner refused to participate in Fox's Jan. 28 presidential debate after the station refused to remove Megyn Kelly as one of the event's moderators.

Americans full of doubts about presidential hopefuls

Nevertheless, the billionaire businessman is not the only one causing concerns, the Washington Post noted. Fifty-one percent of Americans say they had similar doubt about former Secretary of State Hillary Clinton, the Democratic front-runner.

Pollsters discovered, meanwhile, that 43 percent were unsure if they would trust Vermont Sen. Bernie Sanders, Clinton's main challenger, in the Oval Office. And almost 50 percent expressed angst about Texas Sen. Ted Cruz and Florida Sen. Marco Rubio, some of Trump's key rivals in the Republican race.