Sen. Kyrsten Sinema (I-AZ) announced on Tuesday she would not seek a second term, setting her Democratic and GOP challengers up for a two-way race. 

The independent senator’s decision not to run for reelection comes after nearly a year of speculation about her political future. Should Sinema have chosen to run, the race would have put Sinema’s theory that most voters have also spurned their party identity to the test. Polls indicated it would be an uphill climb for an independent to build enough of a centrist coalition to win statewide.