The presidential election of 1800-in which Thomas Jefferson challenged John Adams in his bid for reelection to the presidency-would prove one of the most significant in American history. It was the first election in which political parties played an important role. Jefferson's party, which he called the Republican Party, was only the first iteration of what is today the modern Democratic Party. Over time, the party has remade itself, adapting to the issues of the day and the preferences of its changing constituency. Now the oldest political party in the United States and among the oldest political parties in the world, it is a fixture in American politics, from the local to the national level.