Voters set turnout records in Tuesday's presidential preference elections, which offered Arizona's Republicans and Democrats a rare chance to influence who wins their parties' nominations.
About a million Arizona voters cast ballots in the Super Tuesday contests - roughly half of all those registered with the two major parties.
The heavy turnout came in response to unusually competitive races for both Democrats and Republicans.
"People on both sides of the aisle are expectant that they can win," said Earl de Berge, research director at the nonpartisan Behavior Research Center. "And that generates traffic."
The state's previous two presidential preference elections attracted no more than 35 percent of those registered. Arizona's preference elections are restricted to registered Republicans and Democrats.
Heading into Tuesday's vote, Arizona Sen. John McCain appeared poised to take the lead in the Republican nomination race with a string of victories. However, Mitt Romney and Mike Huckabee, the former governors of Massachusetts and Arkansas, respectively, have kept their campaigns alive with early primary wins.
Texas Rep. Ron Paul has continued to challenge despite several poor finishes.
The Democratic race is far tighter, with New York Sen. Hillary Clinton in a statistical tie with Illinois Sen. Barack Obama across much of the nation.
"It's an exciting election when you think, it's the first time in history that you have a man and a woman vying on one side of the aisle, and then you've got the hometown boy on the other side of the aisle," said Jan Brewer, Arizona's secretary of state.
Arizona was among 24 states in play on Super Tuesday, which combined offered the candidates thousands of delegates. No candidate swept the day's elections.
"These are real contests with real differences between the candidates," de Berg said, explaining why voter turnout surged.
Arizona gives 53 delegates to the Republican primary winner; the Democratic candidates divide 56 delegates based on the percentage of votes they receive.
Many voters waited in long lines, and in unusual polling places, across the East Valley.
Joseph Burks, a 29-year-old Chandler resident, marked his ballot for Obama in an apartment complex's leasing office. Burks said Obama's campaign promise to clear the partisan rancor from national politics swayed his vote.
"I believe he will create the changes we need. He seems to be legitimate," Burks said.
Other voters took advantage of the variety of legitimate candidates.
Brent Richardson, a Queen Creek resident, voted for Huckabee, who won the Iowa caucuses but has struggled since.
A strong showing on Super Tuesday, however, could buoy Huckabee, whose campaign has been the favorite of many evangelical Christians. "I believe God will judge the candidates where they stand morally," Richardson said, "not fiscally."
Even Paul, a Libertarian-leaning Republican who has challenged only in Alaska, continues to battle for delegates. Roger Finnern stood at a busy Tempe intersection Tuesday afternoon, trying to sway undecided voters for the only candidate who wants to abolish the Internal Revenue Service.
Finnern said this race is little different from any other, except for one thing. "The only possible change is getting out of the Bush-Clinton dynasty," he said.
Voters remained in line for hours after polls closed. Despite the turnout, few problems were reported.
Clinton's Arizona campaign issued a news release Tuesday morning alleging widespread voter registration problems.
Brewer said the only issues were with a small number of independent voters who did not know the contests were restricted to members of the major parties.
"As far as procedure, everything's going fine," Brewer said.
Tribune writers Andrea Natekar, Hayley Ringle and Dennis Welch contributed to this report.