Arizona's primary a winner-take-all event

Arizona Republicans head to the polls Tuesday to help pick a presidential nominee.

Polls are open from 6 a.m. to 7 p.m. MST, although many Republicans have already voted.

In the state's two most populous counties, a majority of Republicans who received early ballots had returned them by late last week, officials said. In Pima County, a third of the registered voters overall had already cast early ballots.

Just under 52 percent of the state's registered Republicans voted in the state's 2008 presidential primary, but Maricopa County Election Director Karen Osborne said turnout this year likely will be in the 40-50 percent range.

There's lower interest overall than four years ago due to the lack of a Democratic contest, she said.

Home-state candidate U.S. Sen. John McCain won the Arizona primary four years ago en route to winning the Republican nomination.

This year's Arizona's primary was overshadowed by the Michigan contest the same day.

Both states have nearly the same number of delegates, but Arizona's contest is winner-take-all so a candidate not expecting to win the statewide vote had little incentive to campaign in Arizona.

Romney was the only candidate to run ads in the state, and there was little in-person campaigning by candidates other than right before a debate held in Mesa last week between former Massachusetts Gov. Mitt Romney, former Pennsylvania Sen. Rick Santorum, former House Speaker Newt Gingrich and Texas Congressman Ron Paul.

The debate itself focused on national issues rather than Arizona topics, though illegal immigration and border security did get some attention.

Arizona will send 29 delegates to the Republican convention. That's half of the normal allotment and reflects a penalty imposed because the primary is being held before March 6.