Robert F. Kennedy Jr. has suspended his presidential campaign and endorsed former President Donald Trump, citing concerns about splitting the vote in key battleground states."In my heart, I no longer believe I have a realistic path to electoral victory," Kennedy said. "Now to throw my support to President Trump. The causes were free speech, the war in Ukraine and the war on our children."Trump expressed his gratitude for the endorsement."I want to thank Bobby, that was really nice. That's big," Trump said.Kennedy initially entered the race as a Democrat but later decided to run as an independent."I left that party in October because it had departed so dramatically from the core values that I grew up with," Kennedy said.Kennedy has built a base among voters who identify as anti-establishment and vaccine skeptics."It's always difficult to know what sort of impact a third-party candidate has because they bring a lot of people to the electorate that normally wouldn't vote," said Todd Belt, a political analyst.Belt noted that Kennedy's voters tend to lean toward Trump, and his endorsement could provide a significant boost in swing states."It matters a lot in the swing states. Because, if you remember, in 2023 states, 43,000 votes across three states is all that separated the two candidates," Belt said.Democrats acknowledge the importance of Kennedy's voter base."We'll do all the work necessary to court those voters and make sure that they understand the fundamental stakes and the threat posed by Donald Trump and the path forward, the positive vision that Kamala Harris is campaigning on," said Michael Tyler, the Harris campaign communications director.Kennedy said he made his decision after speaking with Trump over the past several weeks.He also attempted to have similar conversations with Vice President Kamala Harris but did not succeed. Kennedy's ability to remove himself from the ballot in swing states varies by state. Some secretaries of state have indicated it is too late for him to withdraw. In Michigan, for example, a spokesperson said his name will remain on the ballot. In Wisconsin, where Kennedy has filed for ballot access and is awaiting approval, there is "no mechanism for him to 'take back' the filing," according to a Wisconsin Elections Commission spokesperson.Kennedy is currently polling in the mid-single digits in most swing states, according to Real Clear Politics.