It became official this morning:

HOUSTON — Ron Paul, a nine-term Texas congressman who describes himself as a lifelong libertarian, announced his candidacy for the Republican presidential nomination Monday.

Appearing on C-SPAN’s “Washington Journal,” Paul said he was at first reluctant to run, but that “a lot of people want to hear my message and I’m willing to deliver it.”

Paul, who formed an exploratory committee in January, said he has raised more than $500,000 in the past month “with very little effort.”

“So far, the amount of money raised isn’t competitive with those establishment candidates who will raise $100 million, but with the Internet and the amount of money and enthusiasm, I think we can become very competitive,” he said.

Paul, who also ran for the White House as a Libertarian Party candidate in 1988, recently spent three days campaigning in New Hampshire. He is planning campaign trips to Arizona and Iowa, and said he expects to be included in any GOP debates.

An obstetrician-gynecologist from just south of Houston, Paul is ideologically far afield from the Republican mainstream. He has acknowledged that he has been largely shunned by the national party.

Among other differences with his party’s base, Paul has criticized President Bush for acting unconstitutionally in sending U.S. troops to Iraq and has said he would support an investigation into whether Bush “deliberately misrepresented” his reasons for doing so.

“I’m very confident the Republican party has gone in the wrong direction,” Paul said in his C-SPAN appearance. “We used to be the party of small government. Now we’re the party of big government.”