Former President Donald Trump warned against voting for Kathy Barnette in Pennsylvania’s Republican Senate primary in a statement Thursday with less than a week to go before the election.

Trump, who has endorsed Dr. Mehmet Oz in the race, contended that Barnette is incapable of winning in the general election against the “Radical Left Democrats,” whose candidate is likely to be Lt. Gov. John Fetterman.

“Kathy Barnette will never be able to win the General Election against the Radical Left Democrats,” Trump stated.

His warning comes after Barnette surged in recent polls in a race that had initially been a two-way competition between Oz and businessman David McCormick.

Barnette’s spike in support occurred after the most recent Senate debate, in which she revealed in a compelling story that she was a product of rape and that her mother had her at the age of 12.

Barnette’s last-minute success came unexpectedly, as she had previously been polling in the single digits, and federal records showed she had not come near McCormick and Oz in terms of fundraising and spending. Both McCormick and Oz have spent about $14 million compared to Barnette’s $1.6 million, per Open Secrets.

Questions and concerns have since arisen over Barnette’s military background, past comments she has made online, and her overall ability to compete with Fetterman, a popular and well-funded figure among Pennsylvania Democrats.

Trump acknowledged these concerns, saying Barnette “has many things in her past which have not been properly explained or vetted, but if she is able to do so, she will have a wonderful future in the Republican Party—and I will be behind her all the way.”

The most recent poll on the race, taken by InsiderAdvantage/Fox 29 from May 7 to 9, showed Oz in the lead at 22.5 percent, followed by Barnette at 20.9 percent and McCormick at 18.5 percent. All three were within a tight four-point margin, and 25.9 percent of respondents said they were still undecided on a candidate.

The primary takes place next Tuesday, May 17.

Write to Ashley Oliver at aoliver@breitbart.com. Follow her on Twitter at @asholiver.