Republican Arizona Gov. Doug Ducey
"I want to thank Jeff Flake for representing Arizona in the House and Senate for nearly two decades," Ducey said in a statement. "Jeff was a voice for fiscal responsibility at the federal level before it was popular, and effectively ended the practice of earmarks."
"I've appreciated his friendship, professionalism and intellect on policy issues impacting Arizona," Ducey's statement continued.
Democratic Sen. Chuck Schumer of New York
"He is one of the finest human beings I've met in politics," Schumer said in a statement. "He is moral, upright, and strong and he will be missed by just about everybody in the Senate."
Republican Sen. John McCain of Arizona
McCain praised Flake's service and said it will be reviewed as one of "honor, brilliance, and patriotism, and love of country."
"I know you have served Arizona and the country," McCain said. "And there's one thing that I'm absolutely sure of, and that you will continue that service."
Republican Sen. Lindsey Graham of South Carolina
"I'm very saddened and disappointed to hear that @JeffFlake is retiring from the Senate," Graham said on Twitter. "Jeff is one of the smartest, most independent-minded senators in the Republican conference."
"His retirement will be a great loss to the body," Graham continued. "@JeffFlake is a good man who will continue to make contributions to our nation and the conservative cause for years to come."
Source: Business Insider India