Washington (CNN) - It's McCain vs. Obama, Round 2 in Sen. John McCain's new radio ads, the first of his 2010 re-election bid.
"President Obama is leading an extreme, left-wing crusade to bankrupt America," McCain says in one of the new radio ads. "I stand in his way every day. If I get a bruise or two knocking some sense into heads in Washington, so be it," the Arizona Republican also says in the ad.
The second radio ad references McCain's time as a POW during the Vietnam War, saying McCain continues to fight to this day. "John McCain is leading the fight against President Obama every day, standing tall and outspoken, helping Arizona families," an announcer says in the second ad.
"My lot in life has been to wage war against wrong," McCain intones in the second ad, "like today's massive spending at the worst possible time. Send me back to the Senate. We'll win that fight for Arizona."
"Character matters," an announcer says near the end of each ad, in a reference to McCain's reputation as a political maverick who stands on principle.
In an e-mail to his supporters, McCain seeks donations to help keep the new ads on air in Arizona.
McCain faces a possible primary challenge from former Arizona Rep. J. D. Hayworth. Hayworth, an outspoken foe of immigration reform measures championed by McCain, lost his bid for re-election to the House in 2006 and is now a radio talk show host in the state popular with conservative voters. Hayworth has yet to formally announce a bid to challenge McCain, but has hinted on his show at a possible challenge.