With midterms looming, Biden not attending major campaign rallies

One advantage for Democratic candidates like Ms. Porter is financial. The costs of an elaborate campaign stop involving the president, such as a rally, require the party or candidate to bear some of the expensive tab for Mr Biden’s trip – including Air Force One, security secret services and other expenses.

When the president travels for an official White House event, like the one in Irvine, the campaigns don’t bear the cost, even if the candidate attends the event.

Mr Biden’s advisers have downplayed cost savings for candidates as a reason for his mid-term approach, calling it a “benefit” of his travel program at best.

The president’s final push comes at a worrying time for Democrats.

The most recent polls show Republicans have an advantage in the final weeks of the election, with concerns over inflation and a surging economy. In a New York Times/Siena College poll, voters most concerned about the economy overwhelmingly favored Republicans, by a margin of more than two to one.

In Ohio, Representative Tim Ryan, the Democratic Senate candidate, said he would not welcome Mr Biden to his home state, preferring to remain the “face of the campaign”.

Representatives for Senate candidates from Georgia, Wisconsin, North Carolina, Florida, New Hampshire, Arizona and Nevada either declined to comment or did not respond to questions about whether their candidates would accept to campaign with Mr. Biden.

This week Vicki Hiatt, the Kansas Democratic Party chairwoman, raved about Mr. Buttigieg’s arrival, calling him “a very strong, energizing person” and adding that “he’s young, smart. He just – I think he has a lot of energy.