At CNN's town hall on Jan. 25, the Democratic presidential candidates took to the stage for the last time before the Iowa caucuses. Here's what the three candidates said to try to win over voters. (Jenny Starrs/The Washington Post)

DES MOINES -- Sen. Bernie Sanders uttered a handful of words that are likely to hang over his campaign -- and he probably doesn't mind it at all.

"Yes, we will raise taxes," Sanders said during the CNN Democratic forum in Iowa on Monday night. "Yes we will."

For a Democratic audience open to the idea of universal health care, Sanders's comments haven't yet hurt him. But in a general election, where moderate and independent voters are the prize, they could pose more of a problem.

The statement amounts to a ready-made attack ad by political opponents -- particularly Republicans -- who instead will campaign on lowering taxes, especially for the middle class.

But Sanders has staked his entire candidacy on his willingness to bluntly declare that he will not only raise taxes on the wealthy, but his universal health-care plan requires increased taxes that would be offset by cost savings by eliminating monthly premiums and annual deductibles.

Democratic presidential candidate Bernie Sanders arrives for a town hall forum hosted by CNN at Drake University in Des Moines on Jan. 25, 2016. (EPA/Justin Sullivan )

On Monday, he called criticisms of his plan on the grounds that it would raise taxes "unfair" and "demagogic."

His principal opponent, former secretary of state Hillary Clinton, has pledged not to raise taxes on the middle class for any reason, and she has criticized Sanders's plan to implement a Medicare-for-all program as unrealistic.

"We may raise taxes but we are also going to eliminate private heath insurance premiums for individuals and for businesses," Sanders said. "We spend three times more than the British, 50 percent more than the French.

"We can do better than we’re doing right now," Sanders said.