Soon after U.S. Rep. Gabrielle Giffords announced she would resign in January, pundits predicted the special election would be a big-money race influenced heavily by outside political groups.

They were right.

Updated filings with the Federal Election Commission show that, as of Tuesday, more than $2.2 million has been spent by outside political committees on TV and radio ads, mailers and phone calls.

That's on top of what the candidates have spent themselves, which will probably put total expenditures over the $4 million mark for a truncated four-month campaign.

Republican groups have poured in $1.3 million, most of which has been spent on TV ads painting Democrat Ron Barber as a "rubber stamp" for President Obama and his "failed policies."

Democratic groups have spent $921,000, nearly all of that on TV ads hammering Republican Jesse Kelly about his 2010 campaign calling Social Security a "ponzi scheme" and labeling him as too "extreme" for Southern Arizona.

Here's a breakdown of the groups that have spent the most:

• National Republican Congressional Committee - $1 million (which includes $126,000 transferred to Arizona Republican Party)

• House Majority Pac (Demo-cratic PAC) - $472,930

• Democratic Congressional Campaign Committee - $459,580

• American Crossroads (Republican PAC) - $198,504

• American Action Network (Republican PAC) - $73,402

• Freedomworks for America (Republican PAC) - $30,000

By comparison, in the 2010 campaign, which included two years of fundraising and a year of spending, Giffords and Kelly combined to spend $5.2 million.

Contact reporter Brady McCombs at 573-4213 or bmccombs@azstarnet.com