Voters in Arizona are heading to the polls for a special election to fill the seat vacated by Rep. Gabrielle Giffords.
The Democratic lawmaker resigned to focus on her recovery after being shot during a meet and greet event in January 2011.
Giffords has made few public appearances since the shooting. But she has returned to Tucson, Ariz., to campaign for her handpicked successor, Ron Barber.
"We've had other previous special elections of people resigning for personal reasons, or personal scandals, or they are appointed to higher office," Jessica Taylor, a senior analyst at the nonpartisan Washington-based Rothenberg Political Report, told Bloomberg News.
"This is one where a congresswoman had to step down because of a horrific injury -- we're not sure how that will play in voters' minds," she said.
The Republican candidate, Jesse Kelly, is trying to make the election a referendum on President Obama's handling of the economy.
"Emotions are very high. People are very concerned about the economy and tiring of just limping along," John Ellinwood, a spokesman for the Kelly campaign, said.
The race is just one of several election battles across the country Tuesday, including big Senate primaries in Virginia and Maine.