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Arizonans who haven’t already cast their ballot can head to the polls Tuesday. Two of Arizona’s congressional seats are among the most hotly contested races in the nation. Those races and several statewide offices have seen massive spending by candidates and outside groups.

Democratic incumbent Ron Barber and Republican Martha McSally are vying for the 2nd Congressional District seat in a rematch of 2012’s extremely close election. It’s the seat previously occupied by Gabrielle Giffords.

Republican Andy Tobin, speaker of the state House, is taking on Democrat Ann Kirkpatrick in a bid to represent the sprawling 1st Congressional District. Both seats are considered something of a toss-up.

Dark money groups have played a major role in this election, pumping in millions of dollars from donors both inside and outside of Arizona. Republican and Democratic groups have spent heavily on the races for governor and attorney general. There’s also been unprecedented outside money in the usually sleepy Corporation Commission race.

We’ll learn soon if all the money made a difference. Polls close at 7 p.m. The first round of results will be released at 8.