Arizona Gov. Jan Brewer vetoed a bill that would've required President Barack Obama and other presidential candidates to prove their citizenship, calling the legislation "a bridge too far."
The Republican leader said she was troubled that the legislation required Arizona's secretary of state to judge the qualifications of all candidates when they file to run for office.
"I do not support designating one person as the gatekeeper to the ballot for a candidate, which could lead to arbitrary or politically-motivated decisions," Brewer said.
Opponents warned the so-called "birther bill" would be a black eye for Arizona after last year's controversy surrounding the state's strict illegal immigration law.
Under the measure, if there were any dispute about whether a candidate had proved he or she was born in the United States, Arizona's secretary of state would have the final say.
"This measure creates significant new problems while failing to do anything constructive for Arizona," Brewer added.
The bill would have made Arizona the first state to pass such a requirement.
Debate over whether President Obama was born in the United States have led to similar birther bills in other states.