Former Rep. Gabrielle Giffords' handpicked Democratic candidate squared off Tuesday in a special House election in Arizona against the Republican she narrowly beat just months before she was shot. It was a hard-fought preview of the broader fall campaign to come.
Both the GOP and the Democrats were using the race to hone and test their political arguments for the November elections, when everything from the White House on down will be on the ballot.
Republicans, sensing a chance to capture the former congresswoman's seat in southern Arizona, sought to make the contest a referendum on President Obama and his handling of the economy. They argued that Democrat Ron Barber, a former Giffords aide asked by the lawmaker to pursue the seat, would fall in line behind the White House.
Democrats, in turn, played to the senior vote by contending that Republican Jesse Kelly, who narrowly lost to Giffords in 2010, would not protect Medicare and Social Security.
Late poll closings left the winner undetermined late Tuesday night.
The victor will complete the remainder of Giffords' term. Both candidates are promising to run for a full term in the fall, setting up a possible November rematch in a redrawn district that is friendlier to Democrats.
Elsewhere Tuesday, Virginia, Maine, Nevada, Arkansas and South Carolina held primary elections -- with most of those states choosing Senate nominees -- as did North Dakota, where voters decided to let the University of North Dakota scrap its controversial nickname, the Fighting Sioux.
In Virginia, George Allen brushed aside three conservative Republican rivals in a Virginia primary. Allen's victory set up a November clash with another former Virginia governor, Democrat Tim Kaine, in a campaign closely tied to the presidential race in a state both parties consider vital for victory.
In North Dakota, Rep. Rick Berg defeated businessman Duane Sand in a GOP primary. Berg now faces Democrat Heidi Heitkamp in the November race to succeed retiring Democratic Sen. Kent Conrad. The election is expected to play a critical role in determining which party controls the Senate next year.
In Nevada, Republican Sen. Dean Heller and Democratic Rep. Shelley Berkley easily defeated a slate of political unknowns in their respective primaries. Their fall race also will be one of the most competitive in the country.
In Maine, six Republicans and four Democrats were running to fill the Senate seat being vacated by Republican Sen. Olympia J. Snowe. The front-runner, former Gov. Angus King, wasn't on the ballot because he's running as an independent.
No statewide races were part of the Arkansas and South Carolina primaries.
Of all the races Tuesday, the Arizona House race was the most closely watched, partly because of Giffords' absorbing story and partly because holding on to the seat was important for Democrats if they want to regain control of the House.
The party needs big gains in November to grab the majority from Republicans, who now hold a 240-192 advantage with three vacancies, including Giffords' seat.
Republicans, riding high after a decisive victory in Wisconsin's gubernatorial election last Tuesday, set their sights on Arizona. A victory would give party leaders a chance to claim momentum five months before November and fine-tune their plan to link Democratic candidates to Obama.
Giffords, 42, resigned in January to focus on her recovery from a gunshot wound to her head. Giffords and Barber were wounded in the January 2011 shooting rampage outside a Tucson grocery store that killed six people, including a 9-year-old girl and a federal judge.