PHOENIX -- It's the latest attack in what's become one of the most important Senate races in the country right now.
On Monday, Republican Congressman Jeff Flake said his opponent, Democrat Richard Carmona, didn't bother to vote in the 2010 primary or general elections.
Carmona's campaign says he "recalls" voting for Congresswoman Gabrielle Giffords but didn't immediately have the records to prove it.
Officials with the recorder's office in Pima County, where Carmona lives, were unavailable so 3TV couldn't independently verify or refute the claims of both campaigns.
Flake's campaign made the allegations late Monday afternoon shortly after the two candidates finished the second of their three scheduled debates.
"How can Carmona ask Arizonans to vote for him when he doesn't even bother to vote himself," said Flake's communications director, Andrew Wilder, in a statement.
Wilder said the campaign got Carmona's voting record through a public records request. Those documents show Carmona voted in almost every general election since 1994.
The exceptions were 2002 and 2010. There were no records showing that he voted in those years, according to documents obtained by the Flake campaign. But with the exception of 2000 and 2012, there is no record of Carmona voting in a primary election.
Those same records also show Carmona voted for Proposition 100 in a special May election of that year. The ballot measure, which easily passed, asked voters to approve a temporary 1 cent sales tax increase to primarily fund education programs in Arizona.
Andy Barr, the communications director for Carmona, said his boss "recalls voting for Gabby Giffords." Barr said the campaign didn't have the records on hand to show Carmona cast his ballot in the primary or general elections of 2010.
At the time, Giffords was running in a hotly contested general election against a well-financed Republican opponent.
Giffords gave up her seat earlier this year to focus on recovering from the head injuries she suffered during an attempted assassination in January 2011.
The attack from Flake marks the latest in what is an increasingly nasty race for Arizona's first open Senate seat in 18 years. Adding to the political drama is the strategic importance of what was recently thought to be a safe Republican seat.
Democrats are trying to maintain control of the upper chamber after losing the majority of the House just two years ago. Should Carmona win, it would be nearly impossible for Republicans to wrest control of the Senate. But a Flake victory keeps the hopes of Republicans very much alive.
Underscoring the importance of the race is the millions of dollars pouring in from outside groups like the Democratic Senatorial Campaign Committee and its GOP counterpart, the National Republican Senatorial Committee.
According to campaign finance reports, the Democratic Senatorial Campaign Committee has already dropped nearly $1 million on the race. The National Republican Senatorial Committee, on the other hand, has spent about $1.2 million.
Other groups giving big money is the conservative Club For Growth, which has spent $1.1 million helping Flake. In addition, the Democratic-affiliated Majority PAC has spent about $400,000 so far on Carmona.
The money started flowing in only a few weeks after polls over the summer showed Flake had the race in the bag. But that has changed as Carmona has picked up momentum over the past month to make this one of the few contested Senate races in the country.