Texas Governor Rick Perry has announced his candidacy for the Republican nomination in the 2012 presidential race.
In a speech to supporters in South Carolina, Mr Perry slammed the administration of President Barack Obama, saying the US cannot afford four more years of this rudderless leadership.
Former Massachusetts Governor Mitt Romney, the front-runner in national opinion polls, is expected to face a strong challenge from the conservative Mr Perry.
The BBC reports that Mr Perry is a fiscal conservative, and is religious with socially conservative views.
His announcement was made as fellow candidates faced their first key test of grassroots party opinion in an Iowa straw poll.
The first official Iowa primaries in the race for the White House are still several months away but the non-binding results of Saturday's straw poll may play an important role in shaping which Republican will take on Barack Obama.
With Mr Romney not taking part, analysts say the key battle may be between Tim Pawlenty and Michele Bachmann, who are vying for the social conservative vote.