Nov. 8 (Bloomberg) -- Chris Christie's contempt for former House Speaker Newt Gingrich stems from a dispute over a judge.

In their new book about the 2012 presidential election, "Double Down," Mark Halperin and John Heilemann reported that Christie considered Gingrich "the worst human being he had ever met in politics."

That view was forged in early 2011 after Christie appointed Sohail Mohammed, a respected Indian-American lawyer who is Muslim, to the New Jersey Superior Court.

Gingrich, the former House speaker, tried to call Christie to protest the appointment, according to a person familiar with the incident. When he couldn't get through, an agitated Gingrich complained to a Christie aide that the New Jersey governor didn't "understand Sharia law" and the threat it posed. Sharia, or Islamic law, was a pet peeve of Gingrich's, who warned in 2010 that it was "a mortal threat to the survival of freedom in the United States."

That threat wasn't apparent to most experts; it was irrelevant to the Superior Court appointment.

Months later, Gingrich, who was running for president, called to seek the support of the New Jersey governor. Christie refused to take the call, suggesting that an aide tell the Georgia Republican to commit an impossible act.

Mohammed, who had trained Federal Bureau of Investigation and other law-enforcement officers, in Muslim culture, serves on the state's Superior Court.

(Albert R. Hunt is a Bloomberg View columnist. Follow him on Twitter.)