President Biden is sticking to campaigns in deep blue states ahead of the midterm elections, with his low approval rating threatening to harm Democrats running in some of the closest races in the country.

Biden's approval rating has been sitting below 40% throughout October, despite a brief boost to his popularity in August. As a result, Biden has visited fewer than half of the 14 states with the closest congressional and gubernatorial races, and he's visited just one of the four states whose races will determine control of the Senate.

Toss-up Senate races in Arizona, Georgia, Pennsylvania and Nevada are some of the most important in the country, but Biden has only traveled to Pennsylvania.

Biden's slim campaigning schedule is only the latest indicator that Democrats view the president as a potential liability in close races.

WILL BIDEN'S AGGRESSIVE LANGUAGE DIRECTED AT GOP HELP OR HURT DEMOCRATS IN MIDTERMS

President Joe Biden sunglasses

President Biden's approval rating has been sitting below 40% throughout October. (AP Photo/Carolyn Kaster, File)

John Fetterman, Mehmet Oz, Raphael Warnock, Herschel Walker

Pennsylvania and Georgia Senate candidates, from left, Democrat John Fetterman, Republican Mehmet Oz, Democratic Sen. Raphael Warnock, and Republican Herschel Walker. (Hannah Beier/Bloomberg | Mark Makela | Elijah Nouvelage | Megan Varner via Getty Images)

BIDEN INJECTS SOME UNCERTAINTY INTO 2024 WITH HIS ‘MUCH TOO EARLY’ COMMENT

Biden has previously lashed out at reporters who pointed out his lack of presence on the campaign trail.

"John Fetterman is going to appear with you today in Pennsylvania, but there haven't been that many candidates campaigning with you. Why?" a reporter asked in mid-October.

"That's not true. There have been 15! Count, kid, count! Alright?" the president responded.

"OK, and are there going to be even more?" the reporter pressed.

"Yeah!" Biden insisted.

While Democrats in swing states have not criticized Biden outright, some have appeared hesitant to ask for his assistance. Asked whether she would like Biden to campaign for her in New Hampshire last month, Democratic Sen. Maggie Hassan told Fox News that "my job is to be an independent voice for New Hampshire. That’s the role I’ve always worked to play and be for Granite Staters."

President Biden speaks about John Fetterman in Pennsylvania campaign event

President Biden speaks during the Pennsylvania Democratic Party's 3rd Annual Independence Dinner in Philadelphia, Friday, Oct. 28, 2022. (AP Photo/Matt Rourke)

Democrats also received positive news for the key Senate races on Monday, with a New York Times poll showing their candidates leading in Arizona, Georgia and Pennsylvania, while Nevada was tied at a dead heat.

In Arizona, Sen. Mark Kelly, the Democrat, leads Republican challenger Blake Masters 49% to 45%, according to the poll. 

Democratic Sen. Raphael Warnock leads Republican challenger Herschel Walker 47% to 44% in Georgia.

Meanwhile, Democratic candidate John Fetterman leads Republican Dr. Mehmet Oz 49% to 42% in Pennsylvania.

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The U.S. Senate remains a toss-up for the midterm elections, though Republicans are favored to take the House of Representatives.