"My name is Bob Barr and I'm a candidate for the presidency of the United States of America," said the former Republican lawmaker, who played a key role in the congressional impeachment of former president Bill Clinton.

Barr said he was running because there was not "currently or anywhere on the horizon" any candidate who understood the principles of fiscal conservatism and basic principles on which he said America was founded.

The former Georgia congressman, who announced his plans at a press conference here, must first win the Libertarian Party's nomination before throwing himself into the 2008 field for real.

"If Senator McCain ... does not succeed in winning the presidency ... it will be because Senator McCain did not present, and his party did not present, a vision, an agenda, a platform and a series of programs that actually resonated positively with the American people."