Brewer was under tremendous pressure from moderate GOP leaders, including John McCain and Mitt Romney. A coalition of 80 large corps. threatened that such a bill would harm business interests in AZ. Statements from the NFL stoked speculation that it'd would pull out of AZ for the '15 Super Bowl.
http://www.breitbart.com/Big-Government/2014/02/27/Conservatives-Blame-Manipulation-Fear-for-Jan-Brewer-Veto-of-Arizona-SB1062
