President Trump’s allies say they are not terribly worried about the independent presidential candidacy of Robert F. Kennedy Jr., saying the scion pulls far more support from President Biden than he does the GOP. 

Two sources close to the former president say that Mr. Kennedy’s appeal to young people, Black voters, low-information voters, and liberal independents will help to bring down Mr. Biden’s ceiling of support in November’s election.

“RFK is far more of a threat to Biden than Trump based on the polling,” one source in the former president’s orbit said. “He pulls far more from Biden, mostly disaffected Dems and liberal-leaning Democrats than he does from Republicans or conservative-minded independents.”

The source went so far as to say that the GOP “should support his efforts at securing ballot access.”

Mr. Kennedy has already garnered the requisite number of signatures to secure spots on the ballots in two critical swing states — Nevada and New Hampshire. He has also met the signature threshold in Utah and Hawaii. The campaign’s signature-gathering effort is also under way in other must-win states, including North Carolina, Georgia, Michigan, and Arizona. 

Mr. Biden won Nevada by about 35,000 votes in 2020 out of more than 1.5 million cast. The president won New Hampshire by about 60,000.

Another source close to the former president’s campaign operation says that polling indicates Mr. Kennedy’s appeal stretches much further into Mr. Biden’s territory than it does Mr. Trump’s. 

“Voters under 40 just don’t like Biden, and he isn’t polling too well with young Black voters,” the source said, adding that Mr. Biden’s poll numbers represent a prime pick-up opportunity for Messrs. Trump and Kennedy. 

According to a Quinnipiac poll from December, Mr. Kennedy received 22 support nationally, with much of it coming from young, independent, and minority voters.  

In a three-way race with Messrs. Biden and Trump, the independent candidate is predicted to win 36 percent of the independent vote — compared to Mr. Biden at 32 percent and Mr. Trump at 26 percent. Mr. Kennedy also leads both presidents among voters younger than 35, and takes 28 percent of the Black vote compared to Mr. Biden’s 69 percent and Mr. Trump’s 2 percent. 

Mr. Kennedy also takes 12 percent of the Democratic vote from Mr. Biden, polling indicates. 

Mr. Kennedy enjoyed some support from elite Republicans and conservative press figures when he first announced his campaign as a Democrat challenging Mr. Biden for the party’s nomination. He appeared often on Fox News to talk about his isolationist foreign policy, the threat of “the deep state,” and the failings of the incumbent president. 

That changed quickly when he announced his independent bid, and some Republicans felt that his outsider status and anti-establishment rhetoric could eat into some of Mr. Trump’s general election support. 

Fox News’s Sean Hannity was one of the first to turn on Mr. Kennedy when he became an independent candidate. During his Democratic primary run, Mr. Kennedy was often invited on Mr. Hannity’s show to bash Mr. Biden. Mr. Kennedy even did a full-hour live town hall with Mr. Hannity about the president’s failings and the problems with America’s economy

That changed just one day after Mr. Kennedy announced his independent bid on October 9. “You’re pretty liberal,” Mr. Hannity said to Mr. Kennedy at the beginning of their interview on October 10. 

“You’ve called for curbing logging, oil drilling, fracking. You wanted to eliminate it and call it a ‘victory for democracy.’ You want to curb U.S. fossil fuel extraction, keep it in the ground. You once tweeted you want a ban on fossil fuel extraction, a ban on fracking,” Mr. Hannity said of the candidate, invoking the Green New Deal. 

“You called the NRA once a terror group. You supported over the years Democrats Gore, Kerry, Obama, Hillary. You praised Bernie Sanders multiple times. You support affirmative action,” the Fox host said.