Sen. Jon Tester (D-MT), one of the most vulnerable Democrats running for reelection in the 2024 cycle, is changing his stance on the Laken Riley Act after voting against it as an amendment in March.

On Thursday, Tester announced he supported the Republican-led legislation, which advanced from the House of Representatives in March, ABC News reported.

Republican Tim Sheehy, who is running for Tester’s seat, took to X after the Democrat came out in support of the bill, writing, “Flip-Flop Flattop strikes again!”

“The Senate recently defeated the Laken Riley Act by one vote — @jontester’s,” he emphasized.

“Tester’s flip-flop proves he only cares about another term in office,” he added. “Most corrupt, TWO-FACED career politician in the nation!”

The bill — named for the 22-year-old University of Georgia student who was murdered, allegedly by an illegal alien who had previously been issued a citation for shoplifting — would require the Department of Homeland Security to take illegal aliens arrested, charged, or convicted of burglary, theft, larceny, or shoplifting into custody.

Jose Antonio Ibarra (R) is accused of kidnapping and murdering Laken Riley (L) while she went on a morning jog around the University of Georgia on February 22, 2024. (Laken Riley/Facebook, Clarke County Sheriff’s Office)

However, Tester voted against an amendment in March that would have attached “similar language that’s found in the Laken Riley Act” to government funding legislation, the Independent Record reported.

ABC News’s Allison Pecorin wrote:

Tester voted in lockstep with his Democratic colleagues at the time and rejected the bill he’s now co-sponsoring, though a spokesperson for his office told a local outlet at the time that he would have supported the legislation if it came to the floor as a stand-alone measure.

That vote came during the threat of a potential government shutdown.

“If the Laken Riley amendment would have passed, the bill would have to return to the House for a vote, which would have triggered a partial government shutdown,” the Independent Record reported in late April.

Fox News, citing three anonymous Republican sources, reported at the time that Tester was “particularly against being on record on the Laken Riley Act.”

A J.L. Partners poll, taken after Tester voted against the amendment, found that he trailed Sheehy by a margin of 48 percent to 45 percent. The lead was within the ± 4.3 percent margin of error, per the Independent Record.  The poll was taken March 26-29, 2024, among 503 likely voters.

National Republican Senatorial Committee spokeswoman Maggie Abboud ripped Tester for his sudden change in position in an emailed release.

“Jon Tester’s support for Joe Biden’s open borders agenda is hurting his reelection campaign, so he is flip-flopping. Montanans can’t trust Two-Faced Tester,” she said.