GOP challenger to Sen. Richard Lugar to launch campaign

Indiana state Treasurer Richard Mourdock will formally announce on Tuesday that he'll challenge veteran U.S. senator Richard Lugar in the GOP primary, setting up a key intraparty fight.

Mourdock told The Washington Post and Roll Call today that he'll disclose a list of supporters, including a majority of the state's Republican county chairmen and the state GOP executive committee.

Lugar, 78, is the longest-serving senator in Indiana history. He hasn't faced a primary challenge since he was first elected to the Senate in 1976. The senator announced last month he would seek a seventh term.

Lugar's re-election race is being closely watched, in part because of his age and because of the rise of the small-government, anti-tax Tea Party movement which successfully challenged veteran GOP senator Robert Bennett of Utah in the 2010 elections.

Mourdock told Roll Call that he will fight any attempt by Lugar or his campaign to be labeled a Tea Party candidate. At an event for Ronald Reagan's birthday, Mourdock said he believed that "competition in Republicanism" is important and that he wanted a "competition of ideas" in the primary.