Gabrielle Giffords' decision to resign from Congress will force Gov. Jan Brewer to call an April special election to replace her.
The governor will set the date for special primary and general elections to determine who will serve the remainder of Giffords' term, which expires Dec. 31.
There's a great deal of speculation about who will run, how much it will cost and if Gifford's will endorse a candidate in the primary.
Giffords plans to turn in her resignation to Brewer shortly after President Barack Obama's State of the Union address on Tuesday night.
"Upon the Congresswoman's office being officially declared vacant, I will call a special primary and general election in order to fill the 8th Congressional District vacancy, in accordance with Arizona law," Brewer said in a statement Sunday. "The winner will complete the remainder of Congresswoman Giffords' term, which expires at the end of 2012."
The governor has 72 hours to set the special election after receiving Giffords' resignation.
Under Arizona law, a special congressional election can only be called by the governor for that purpose. It must be held no sooner than 80 days and no later than 90 days after receiving the resignation.
A general election must be held 50-60 days after the primary.
Before Giffords announced her plans, several candidates established exploratory committee to test the waters for a possible run.
Republican state Sen. Frank Antenori, R-Tucson, and Dave Sitton, a University of Arizona sports broadcaster, have expressed interest in running. Jesse Kelly, Giffords' 2010 GOP opponent, might run again. Republican Adam Hansen of Bisbee also has announced his candidacy.
Antenori said Monday he will not discuss his plans until Giffords finishes her duties in Congress.
"At this time, the focus of attention in Southern Arizona needs to be honoring the congresswoman's service and the sacrifice she has made in service of her fellow Arizonans," the state senator said.
Sitton said Sunday he will meet this week with his exploratory committee this week.
Democratic state legislators Paula Aboud, Steve Farley and Matt Heinz of Tucson have been mentioned as possible Giffords replacements.
Giffords' chief of staff Pia Carusone and state director Ron Barber have been mentioned as well.
Giffords' husband, former astronaut Mark Kelly, repeatedly has said he isn't interested in running. He said he is focused on Giffords' recovery from the Jan. 8, 2011 mass shooting in Tucson, which killed six and injured 13.
Heinz said Monday: "Yesterday's announcement from Rep. Giffords marks a sad day for our state. Like all Southern Arizonans, I'm deeply saddened at the news that she intends to step down from Congress. It was my hope that she would be back on the campaign trail this year and would serve her constituents for many years to come. She will be greatly missed, but I respect her decision and wish my friend Gabby nothing but continued health and happiness on her road to full recovery."
The special election will be based on current boundaries of Arizona's 8th District. The November election will be held under the new redistricting map.
Candidates who want to run in the special election will have 30 days from Brewer's announcement to collect 800 signatures from registered voters to qualify for the ballot.
At issue for the candidates: Who can raise a lot of money very quickly.
The special election promises to be expensive.
"I look for more money to be spent in the special election than the general election," Pima County Democratic Chair Jeff Rogers said.
That's because the special election will be the only race going at the time whereas the general election will have all the races in play.
Plus, it's Gifford's district which the Democrats want to hold and the Republicans want to take.
It has an aura which is attractive to both parties.
Also, since the US Supreme Court's decision allowing unlimited independent money to be spent on campaigns, Super PAC's have become popular.
Some look for very deep pocketed organizations to target the district.
The candidates spent nearly $6 million in the off year 2010 election and outside groups added at least that or more.
It's likely this race could exceed that.
Money will be a much talked about part of the race.
Besides the special election, the winners will have to turn around to run in the general election in the fall.
For the winner, it could conceivable be four races in eight months.
It's also possible, as some Democrats have hinted at, that a candidate with very deep pockets could announce.
It would avoid the need to raise cash quickly but it could also cause the race to devolve into a spending spree as the GOP races to catch up.
There's also the question of whether Giffords will endorse one of the candidates.
Rogers believes it's "highly likely."
It's her seat so there would be nothing wrong with her picking someone to finish her term.
Then there's the problem that the special election will be held for Congressional District 8 but the general election in the fall with be under the new district boundaries in what is now District 2.
The makeup of the district goes from a 5-percent-point advantage for the GOP to the most competitive district in Arizona, with an equal number of R's and D's.
Speculation runs deep right now but the only thing that appears certain is that the race will be expensive.
Copyright 2012 Tucson News Now. All rights reserved.