Donald Lambro

Buried within a recent presidential-preference poll that asked voters who they would never vote for, an unexpectedly large number gave an emphatic thumbs-down to Democratic front-runner Hillary Clinton.

A national poll of likely voters by independent pollster John Zogby found that nearly half (46 percent) said they couldn't vote for the former first lady under any circumstances. That is certainly a huge portion of the American electorate, which will no doubt feed growing doubts in her party about the New York senator's electability. But another number was even more disturbing to senior advisers in her campaign.

Zogby found that among likely Democratic voters, 18 percent said they "would never cast a vote in Clinton's favor."

That such a large percentage of overall voters would flatly express an aversion to electing her president was troubling enough to top Democratic officials. But that she appeared to be losing support within the base of her own party set off alarm bells among her high command.

The 46 percent of overall voters "includes a significant number of Republicans, conservative-leaning independents, liberal anti-war people who don't trust her, plus those who don't like her for a number of reasons, including those who consider her polarizing or feel she can't win," Zogby told me last week.

"If there's 46 percent who say never, then there are the rest of the voters who can be drawn from. But when I see 33 percent who say they could never vote for Barack Obama or John Edwards, and even Al Gore has less than that, then there is a problem with her and her campaign," he said.

The 18 percent figure surprised Zogby. "That is nearly one in five Democrats. The parties are at parity, which means she's going to need 85 percent support among Democrats," he said. Losing 18 percent of the Democrats means she would fall short of the minimum support needed to clinch the presidency.

One Democratic pollster, Ed Sarpolus of Michigan's EPIC-MRA poll, said, "She's in a trouble zone."

"Typically, when a candidate loses more than 12 percent of the base, they tend to lose," he continued. "If it was 12 percent, I wouldn't be overly concerned. If it gets around 15 percent, there are enough Democrats who would hold their noses, cover their eyes and vote for Hillary on Election Day."

But beyond that number, should it continue to hold up, "it is very difficult to win," he said.

However, Zogby's poll also showed that 19 percent of the Democrats said they could never vote for Obama, her closest rival for the nomination, or for Edwards, both of whom are in the top tier.

Donald Lambro

Donald Lambro is chief political correspondent for The Washington Times.