Found this article interesting
On June 8, 1966 the NFL and AFL announced a merger, but in order to avoid antitrust law sanctions, the merger had to be approved by the United States Congress. And that meant convincing the powerful Louisiana Senator and Chairman of the Finance Committee Russell Long. According to the Senate’s own website, Chairman Long tacked the merger onto a tax bill, ensuring it would arrive at his desk. He could then alter the language, ensuring exemption from sanctions. In exchange, Long told NFL Commissioner Pete Rozelle that he wanted the next NFL expansion franchise to be in New Orleans, in Long’s home state of Louisiana. The merger passed and on November 1, 1966, the New Orleans Saints became the sixteenth NFL franchise. Good old fashion backroom politics.