A bill allowing religious business owners to refuse service to homosexuals has put the governor of Arizona under intense pressure following protests from major US companies such as Apple and American Airlines.
The corporate giants have led an unprecedented business intervention into the debate over gay rights.
They have even suggested that next year's Super Bowl, a major economic windfall, could be pulled out of Arizona if the bill becomes law.
The uproar has alarmed Republicans trying to rehabilitate their party's image.
Known as SB 1062, the bill is now on the desk of Jan Brewer, Arizona's conservative Republican governor, who has until Saturday to sign it into law or exercise her power of veto.
The proposal will automatically become law if the governor takes no action. NBC reported she was likely to veto.
An Apple executive involved in opening a new plant in Arizona called the governor about vetoing the bill. (© Daily Telegraph. London)