Montana Senate race now considered a toss-up as Tester's lead shrinks.

A political expert has revised its forecast for the November Senate election in Montana, predicting a Republican advantage, as Democratic Senator Jon Tester's polling numbers have decreased.

On Friday, Sabato's Crystal Ball at the University of Virginia's Center for Politics shifted the battle between Tester and Republican Senate candidate Tim Sheehy, a former Navy SEAL, from a "toss up" to "leans Republican" with less than nine weeks until the election.

A new AARP poll released on Thursday showed Sheehy leading Tester by six points in a two-way race, with a 51%-45% advantage. In an expanded field, Sheehy still emerged victorious with a 49%-41% margin.

""As previously mentioned, Tester faces an uphill battle in the upcoming election, with history and recent trends not favoring him. He is one of a few partisan outliers in Congress, holding a Senate seat that the other party won by 16 points in the most recent presidential election," wrote managing editor Kyle Kondik."

If ticket-splitting returns this year, Tester may still survive. However, the long-term trend indicates a decline in ticket-splitting.

Neither Tester nor Sheehy's campaigns responded to Planet Chronicle Digital's inquiries.

Since his initial election to the Senate in 2006, Tester has been re-elected by Montanans twice, defying the state's traditional Republican voting pattern.

In 2018, the Democratic senator's re-election was not tied to a presidential election, allowing him to focus solely on his race. However, with Vice President Kamala Harris as the Democratic nominee and former President Trump leading the Republican ticket in Montana, the senator's race is now tied to the presidential race.

Although Tester did not endorse Harris and did not attend the Democratic National Convention, it is unclear how effective his strategy was, especially since he was responsible for recruiting Harris for the Senate in 2015.

The Montana Democrat endorsed Kamala Harris as Vice President when she was chosen by President Biden in 2020. He wrote on X, "My friend @KamalaHarris is a proven fighter and an excellent pick for Vice President. As VP, I'm confident she will continue to fight for working families across this country. Looking forward to supporting her and @JoeBiden in November."

Recently, Tester stated that he would not endorse for the presidential race and provided a reason.

He explained his decision not to endorse Harris by stating two reasons: firstly, he is focused on his race, and secondly, the race is not about national politics but rather Montana.

Planet Chronicle Digital's Aubrie Spady contributed to this report.