 Sean O'Brien told the crowd he was honored to be the first Teamster in the union's 121-year history to address the Republican National Convention. Today, the Teamsters are here to say we are not beholden to anyone or any party. He said he was here on behalf of working-class Americans. O'Brien did not endorse Donald Trump, and the Teamsters may not formally back any candidate in what would be a blow to Joe Biden, who enjoys union support. Greg Clugston, Milwaukee.