Democrats are tied to Biden, despite attempts to distance themselves.

Some of the most vulnerable Democratic Senate incumbents up for re-election in November have looked to highlight their disagreements with President Biden ahead of the pivotal matchups.

"'Distancing' from a party brand is a time-honored tradition in Congress," explained Jacob Neiheisel, associate professor of political science at the State University of New York at Buffalo.

Sens. Jon Tester, D-Mont.; Sherrod Brown, D-Ohio; Tammy Baldwin, D-Wis.; Jacky Rosen, D-Nev.; and Bob Casey, D-Pa., are embroiled in the most competitive races of the 2024 cycle, with the Democrats up against one of the toughest re-election maps in years.

"They're going to sound like MAGA Republicans in their TV ads before it's all over with," said Republican strategist Scott Jennings.

Last week, Tester came out in favor of a largely Republican-supported illegal immigration measure named after slain Georgia college student Laken Riley. He previously voted against moving forward with the bill, which takes aim at illegal immigrants like the one charged with Riley's murder, as a potential amendment to a larger bill package. However, Tester did signal at the time he would support it if it came to the floor as a stand-alone bill, despite the unlikelihood of Senate Majority Leader Chuck Schumer, D-N.Y. allowing that to happen.

Tester's office vehemently pushed back on previous claims that he was against the bill. "Claims from Mitch McConnell-backed groups that Senator Tester changed his position on the Laken Riley Act are patently false and another desperate attempt to politicize the border instead of fixing it," his office told Fox News Digital.

The Montana senator isn't the only one to make his differences with Biden clear in the lead-up to the election.

Rosen, who represents the critical swing state of Nevada, also diverged with Biden publicly on multiple occasions. In particular, Rosen is partially credited with killing the Biden administration's hopes of confirming the first Muslim federal appellate judge in Adeel Mangi. The Nevada senator came out against the controversial Biden nominee, citing his ties with an allegedly anti-law enforcement organization.

"This is what they do," Jennings said. "They spend five and a half years supporting Democrats and Democratic policies that everyone in their state hates. And then they spend six months pretending it never happened."

The Republican strategist added, though, that they may be hard-pressed to convince voters of their differences with the president, given that they vote in line with him nearly all the time.