Robert F. Kennedy Jr. is making targeted appeals to Donald Trump supporters, pledging to "seal the border" from undocumented migrants and investigate the prosecutions of pro-Trump rioters who attacked the Capitol on Jan. 6, 2021.

Why it matters: Kennedy's long-shot independent campaign so far appears to be hurting President Biden more than Trump in polls, but Kennedy's latest moves could flip that equation.

• Kennedy is now drawing fire from Trump and other conservatives who once hailed Kennedy's campaign.

Driving the news: In late March, Kennedy put out a YouTube ad showing him at the southern border with a line of detained migrants.

• "This is a humanitarian crisis because of the understanding across the globe that we now have an open border here," Kennedy says in the ad, echoing some of the language Trump has used.
• In another ad on X, Kennedy says he will "seal the border to illegal immigration" to solve the "border crisis."
• Unlike Trump, however, Kennedy pledges to "expand lawful and fair immigration."

Zoom in: Last week, Kennedy said he'd appoint a special counsel to investigate the prosecutions of the convicted Capitol rioters who tried to overturn the 2020 election results and give Trump a second term.

• Kennedy said: "As president, I will appoint a special counsel — an individual respected by all sides — to investigate whether prosecutorial discretion was abused for political ends in this case. And I will right any wrongs that we discover."
• More than 500 people have received home detention or prison sentences for their actions that day in one of the largest Justice Department probes ever. Trump has called them "hostages."

Kennedy also falsely said last week that the rioters "carried no weapons," before acknowledging he had been "incorrect" and that "several have been convicted of carrying firearms into the Capitol."

• In a campaign email last week that Kennedy later disavowed, the campaign described the rioters as "activists sitting in a Washington, D.C., jail cell stripped of their constitutional liberties."

Between the lines: Kennedy was drawing support among some Republicans even before his recent efforts.

• He gained a following on the right during the pandemic with his vaccine skepticism and his book, "The Real Anthony Fauci: Bill Gates, Big Pharma, and the Global War on Democracy and Public Health."

Right-wing media also boosted Kennedy when he was running against Biden in the Democratic primary — before he was seen as a potential threat to Trump in November.

• Trump also reportedly mused about a Trump-Kennedy ticket because he liked the way it sounded or would look on a bumper sticker, as The New York Times and The Bulwark reported.

After Kennedy began running as an independent last fall, conservatives and the Trump campaign began attacking him. They've stepped up those attacks recently.

• "RFK Jr. is the most Radical Left Candidate in the race, by far," Trump wrote on Truth Social last month. "He's a big fan of the Green New Scam, and other economy killing disasters."
• Last week, Fox News host Sean Hannity said on his show that some Republicans may think Kennedy is a conservative, but that he's actually a "devout, radical environmentalist."
• Biden's campaign also is going after Kennedy, with the Democratic National Committee bringing on campaign veteran Lis Smith to lead the communications charge.

What they're saying: Kennedy spokesperson Stefanie Spear told Axios: "We are neither right nor left, neither liberal nor conservative."

• She added that both parties "are screaming, 'He's one of THEM!' Our ticket represents the broad majority who have unsubscribed from the right-left paradigm."
• "RFK Jr. is a spoiler for Donald Trump," said Matt Corridoni, a DNC spokesperson.
• He added that Kennedy is "now providing Trump cover by parroting MAGA talking points downplaying January 6th."
• A Trump campaign spokesperson did not respond to a request for comment.