Republican candidate John McCain declared on Thursday that he was constitutionally qualified to be president of the United States, although he was not born in a U.S. state. The 72-years-old Arizona Senator, who was born in the Panama Canal Zone, told reporters that he was not concerned as regards this matter. He said that he has asked conservative lawyer Ted Olson to make some research viewing the legitimacy of his candidature.

According to the findings, the Panama Canal Zone was controlled by the U.S. government at the time when McCain was born on August 29, 1936, and his father was serving with the U.S. Navy in the zone, Reuters reports.

“It's very clear that an American born in a territory of the United States, whose father is serving in the military, would not be eligible for the presidency of the United States is certainly not something our founding fathers envisioned,” said the Arizona senator.

The U.S. constitution states that only “natural-born citizens” can candidate for U.S. president.

But this issue was put to rest 44 years ago when Barry Goldwater ran for the White House. Goldwater was born in Arizona in 1909, before it became a state. Republican Goldwater ran for president in 1964, and lost the election to Democrat Lyndon Johnson.

“Barry Goldwater was born in Arizona when it was a territory, Arizona was a territory, and it went all the way to the Supreme Court. And there's no doubt about that. And it was researched again in 2000,” McCain told reporters Thursday, the Associated Press reports.

This constitutional requirement prevents some important US politicians from running for presidency, as for instance the California Governor Arnold Schwarzenegger, who was born in Austria, or Michigan Democratic Gov. Jennifer Granholm, who was born in Canada.

Missouri Senator Claire McCaskill introduced Thursday a bill that states that anyone born to any U.S. citizen while serving in the U.S. armed forces should be considered a “natural-born citizen.” Democratic candidate Barrack Obama expressed his support for the bill.

“Those who serve and sacrifice for their country, like John McCain and his father, deserve every honor and privilege that our nation can possibly provide, and that includes the ability to run for the highest office in the land,” Obama said in a statement.