In 2003, Cleland began working for the 2004 presidential campaign of Massachusetts senator John Kerry, also a Vietnam veteran; Kerry went on to win the Democratic nomination. Cleland often appeared at campaign events with Kerry and was considered by many to be one of his most important surrogates, partly as a symbol of the sacrifices made by soldiers for wars. He went to Bush's Texas ranch to deliver a swift boat ad complaint, but the event failed to have much impact. On July 29, 2004, Cleland introduced Kerry with a speech at the Democratic National Convention.