In a new campaign ad that doubles as a confessional, former New Jersey Gov. Chris Christie tells voters he has "an admission to make."

Why it matters: Christie, who's been particularly critical of Trump during his campaign, is trying to win over voters who, like himself, backed Trump in the past and now are wary or disillusioned.

What he's saying: "Eight years ago when I decided to endorse Donald Trump for president, I did it because he was winning, and I did it because I thought I could make him a better candidate and a better president," Christie says in the ad, speaking directly to the camera.

• "Well, I was wrong, I made a mistake," he says.

Driving the news: The new digital ad is part of a previously announced seven-figure ad buy that includes a series of direct-to-camera ads Christie's campaign is showing in New Hampshire in advance of its presidential primary on Jan. 23.

• Christie's team says it's targeting ads this week to areas where rival Nikki Haley is hosting town halls. "We will continue to do so as we make the contrast in style and willingness to the tell the truth as clear for voters as possible," said a Christie spokesperson.
• In the new ad, Christie says this moment is similar to 2016, when he endorsed Trump. Today, "Donald Trump is ahead in the polls and so everyone says, 'Anyone who's behind him should drop out, and we should make our choice: Donald Trump versus Joe Biden.' "
• "Neither choice is acceptable to me," Christie adds, "and it shouldn't be acceptable to you."

Between the lines: Some Republican strategists have argued that Christie should drop out to consolidate the field against Trump,. In an ad last week he addressed the chatter, saying, "Some people say I should drop out of this race. Really?"

• Polls have shown Christie trailing Haley and Trump in New Hampshire, and Christie has acknowledged that he needs a strong finish in the state to continue his campaign.
• On MSNBC's "Morning Joe" Wednesday, Christie added: "Anybody thinks I'm getting out of this race, they're crazy."
• He has continued to ramp up his attacks on Haley and Florida Gov. Ron DeSantis, arguing that they are largely attacking one another instead of Trump in order to to set up bids for president in 2028.