Robert F. Kennedy Jr. is lashing out after being left out of the upcoming presidential debates between Joe Biden and Donald Trump that are scheduled for June and September.

Kennedy, who is unlikely to meet the debate qualification requirements laid out by CNN, said in a social media post that the president and former president are “trying to exclude me from their debate because they are afraid I would win.”

“Keeping viable candidates off the debate stage undermines democracy,” Kennedy, who is attempting to mount an independent campaign, wrote on X.

The Biden and Trump campaigns announced within minutes of each other earlier Wednesday that they had accepted invitations to debate on CNN on June 27 and on ABC News on Sept. 10.

Previously, both candidates said they would not participate in the Commission on Presidential Debates’ proposed schedule, which led to doubt on if any debates would occur at all.

A poll released Monday found Kennedy drawing a similar level of support from both Biden and Trump. He’s officially made the ballot in Michigan and is still attempting to qualify in other key states.

According to CNN’s rules, a candidate must be on the ballot in enough states to earn a majority of Electoral College votes by June 20.

Although the Kennedy campaign is making efforts to meet the state-by-state qualifications to get on the ballot, many of the states won’t certify the candidates who have qualified until later in the summer.

“If Americans are ever going to escape the hammerlock of the two-party system, now is the time to do it,” Kennedy wrote. “These are the two most unpopular candidates in living memory.”