Arizona Gov. Jan Brewer (R) has signed a controversial immigration bill which will authorize state authorities to request an immigrant's documentation.

Brewer faced a difficult political decision, given that she wasn't elected to her current post (she succeeded now-Homeland Security Secretary Janet Napolitano) and that she faces opposition in both the primary and general elections. 

Her primary opponent, state Treasurer Dean Martin, called on her to support the bill. But signing it risks turning off voters -- especially Latino ones -- in the general election.

Sen. John McCain (R-Ariz.), who also faces a primary, recently spoke out in favor the bill, despite his past emphasis on a more comprehensive immigration policy. President Obama on Friday called the bill "misguided."

For more on the bill, see here.