Homeland Security Secretary Janet Napolitano told the Associated Press on Friday that she will not seek the open Senate seat in Arizona.
The former governor said she wants to remain in the administration, which she joined in January 2009.
Rep. Jeff Flake (R) is so far the only announced candidate in the race, although several members of both parties are taking a look at the rarely open Senate seat.
Flake released today a list of his top supporters whom he has named as campaign co-chairmen and committee members. The six-term Congressman already has the support of the anti-tax group Club for Growth, which announced raising $100,000 for him in one day.
Roll Call Politics rates this race Leans Republican.