A month ago, Newt Gingrich pleased Jewish conservatives when, during his address to the Republican Jewish Coalition’s presidential forum, he promised to make former U.S. Ambassador to the United Nations John Bolton his secretary of state. But the offer of the State Department wasn’t enough to entice Bolton to return the favor and endorse Gingrich’s presidential ambitions. Last night, Bolton told FOX News he was backing Mitt Romney.

Bolton said he was “following the William F. Buckley test” in backing the most conservative candidate who can get elected, which he believes is Romney. Since, in his view, the re-election of Barack Obama would be a disaster for U.S. foreign as well as domestic policy, Romney presents the best chance for Republicans to avert that possibility.

At the time that he spoke of making Bolton his secretary of state, Gingrich admitted he hadn’t made the offer in person. Bolton said he was flattered but declined to back the former speaker’s campaign.

Bolton toyed with a presidential run himself but eventually rightly decided he had little chance. As for Romney’s conservative bona fides, Bolton said he “was conservative enough for me.” Bolton conceded there was little difference between the foreign policy stances enunciated between his choice and that of Gingrich and even Rick Santorum or Rick Perry. But he praised Romney’s belief in American exceptionalism and his support for revitalizing America’s military might. According to the Daily Caller, Romney has praised Bolton’s ideas for reorganizing the State Department.

Asked by Greta van Susteren as to what was Obama’s biggest foreign policy mistake, Bolton answered without hesitation that it was his failure to adequately deal with the threat of a nuclear Iran.