Arizona Sen. John McCain's possible primary challenger is now official. Former congressman J.D. Hayworth -- voted out of office three years ago -- is making his political comeback in this year's Senate Republican primary, challenging McCain from the right. After filing official papers last week, Hayworth will formally announce his candidacy Feb. 15.

Hayworth launched a robo-call campaign last week to persuade GOP voters that McCain had been in office for too long and that his voting record was too moderate. A poll released two weeks ago found McCain leading by 22 points.

"Chuck Todd and many others are right. This will be one of the hottest races in the country because this will be democracy at its very best," Hayworth said in a released statement, noting Todd calling this a Top 10 primary on his MSNBC morning show last week. "It will be an intense debate between a moderate with a transparent election year conversion and a conservative willing to respect but also stand up to the flip-flops and unreliability of a moderate masquerading as a maverick."