The president of the Teamsters Union is set to speak at this summer’s Republican National Convention. Trump said on social media that Sean O'Brien had “accepted” his invitation to address delegates in Milwaukee next month. Teamsters spokesperson Kara Deniz says that O’Brien requested a speaking slot at both major party conventions. Trump, the presumptive GOP nominee, is trying to chip away at President Joe Biden’s support among the blue-collar workers, who will likely play a major role in the general election. Both Trump and Biden have met with Teamsters leaders this year. DNC officials did not immediately respond to whether O'Brien would speak at their event. The union has endorsed Democratic candidates in the last two presidential cycles.