Though Miller is a Democrat, which in his lifetime has definitely become the more liberal party in America as opposed to the Republicans, he is widely known as a conservative populist. Though he saw the Democratic party's complete control of Georgia fall apart during his time as lieutenant governor and governor, he has always remained popular and won his elections easily, showing his ability to please most members of both parties in Georgia. On the other hand, he has always refused Republican offers to join their party, remaining loyal to the Democrats. During 2001 and 2002, when liberal Republican senators from New England such as James Jeffords and Lincoln Chafee threatened to, and, in Jefford's case, did, leave the Republican party, rumors abounded that Miller would become a Republican and give control of the senate back to that party. These rumors, were, however, always denied. In 2003, he announced his retirement from politics, saying that he would finish his term in the Senate but not seek reelection. He also announced that he would be supporting George W. Bush in the presidential election rather than any of the nine candidates currently competing for the nomination of his own party, though he again denied that he would officially become a Republican.