Sen. John McCain (R-Ariz.) raised $2.2 million in the first three months of 2010, as he sought to build his campaign war chest to fend off a primary challenge from former Rep. J.D. Hayworth (R-Ariz.).

McCain’s campaign issued a statement Wednesday announcing his fundraising total and the fact that the incumbent will end March with $4.5 million in cash on hand.

Hayworth, who launched his campaign in February, has yet to disclose any fundraising totals. However, his campaign Web site reports that Hayworth has raised $820,000 as part of a “Million Dollar March” online fundraising initiative.

Democrats sense a growing opportunity in Arizona given the likelihood of a hard-fought GOP primary, but they may have a competitive intraparty contest of their own to contend with.

Excitement is growing around the possible candidacy of Nan Stockholm Walden (D), an attorney and owner of a 7,000-acre pecan farm south of Tucson.

But if Walden runs, she is likely to have to contend with Rodney Glassman, the youthful Tucson City councilman who has been exploring the race for over a year and is expected to run.

The primary is scheduled for Aug. 24.