Trump Attacks RFK Jr., a Third-Party Wild Card

Former President Donald J. Trump attacked Robert F. Kennedy Jr., the independent presidential candidate, on Wednesday morning, casting Mr. Kennedy as a liberal Democrat in disguise while also seeming to back him as a spoiler for President Biden’s campaign.

Mr. Trump, the presumptive Republican presidential nominee, pointed in particular to Mr. Kennedy’s views on climate change and the environment, writing on his social media site that Mr. Kennedy was more “radical Left” than Mr. Biden.

Yet he also professed support for Mr. Kennedy’s campaign, claiming that Mr. Kennedy would be likely to siphon votes from Mr. Biden. “I love that he is running!” Mr. Trump concluded.

Mr. Trump’s post, which came a day after Mr. Kennedy announced his running mate, underscores the political wild card that is Mr. Kennedy’s bid. Even as Mr. Trump asserted that Mr. Kennedy’s independent campaign would be a boon to his own effort to beat Mr. Biden, two Trump campaign officials said they had seen polling that showed Mr. Kennedy drawing support from independent voters in a way that could be equally detrimental to both Mr. Trump and Mr. Biden.

Though Mr. Kennedy will face challenges getting on the ballot in several states, it is possible that his campaign could tip the scales in battlegrounds where the margins of victory have been narrow in recent election cycles.

Mr. Kennedy’s campaign did not respond to a request for comment. But on Tuesday, he made clear his intention to court voters who have soured on both candidates. “Our campaign is a spoiler all right,” he said during his announcement. “It is a spoiler for President Biden and for President Trump.”