Arizona Sen. John McCainJohn Sidney McCainLawmakers worry about rise of fake video technology Democrats put Dreamers and their party in danger by playing hardball Trump set a good defense budget, but here is how to make it better MORE (R) applauded his state's governor, Jan Brewer (R), Monday for vetoing a controversial "birther" bill.

The legislation, the first of its kind in the nation, would have required presidential candidates to prove their citizenship to be included on the state's ballot. 

McCain, President Obama's GOP opponent in 2008, tweeted:

Proud of @GovBrewer for her veto of the "birther bill" - it was the right decision.

The bill stemmed from suspicions of some of Obama's opponents that he is not a natural-born citizen of the United States and is thus ineligible to be commander in chief.

McCain's 2008 campaign investigated "birther" claims against Obama, but found them to be baseless. In 2010, the senator ran a campaign ad during his Senate reelection bid against his Republican primary opponent, former Rep. J.D. Hayworth, tying him to top figures in the "birther" movement.

In a letter explaining her veto, Brewer said the proposal, "creates significant new problems while failing to do anything constructive for Arizona," according to the Arizona Republic.