Sinking in the polls and struggling against the perception that she is untrustworthy, on Tuesday evening Democratic front-runner Hillary Clinton reversed course and apologized for her use of a private e-mail server while she was secretary of state.

“That was a mistake,” Clinton told ABC News’ David Muir, according to a report on the interview, which is set to air Tuesday evening on ABC. “I’m sorry about that. I take responsibility, and I’m trying to be as transparent as I possibly can.”

The mea culpa is a dramatic shift for the former secretary of state, who as recently as last Friday refused multiple invitations from NBC’s Andrea Mitchell to say sorry for putting classified material at risk. “I certainly wish I had made a different choice,” was the most she would admit to last week. “At the end of the day, I am sorry that this has been confusing to people and has raised a lot of questions.”

When news of the scandal first broke in March, Clinton claimed that she had done nothing wrong and had never sent or received any classified information. When that turned out not to be true, her campaign shifted to the claim that any sensitive information had been classified retroactively by State Department reviewers. That contention is now under increasing scrutiny, with two separate intelligence community probes concluding that at least two of the e-mails were designated “Top Secret” from Day One.

#share#New polling since last week’s interview may have prompted the shift in Clinton’s tone. A Monmouth poll released over the weekend shows a ten-point drop in Clinton’s support among Democrats, from 52 percent one month ago to 42 percent support now. At 22 percent, Joe Biden is rapidly closing on Clinton, despite the fact that the vice president has yet to declare his candidacy. And multiple polls in the past month have revealed voter skepticism toward Clinton, with most showing that 60 percent or more believe her to be dishonest.

— Brendan Bordelon is a political reporter for National Review.