Ronald Reagan’s 11th Commandment was, “Thou shall not speak ill of other Republicans.”

Would that Newt Gingrich had remembered and honored it before he accused fellow Republicans of social engineering. This is a classic example of “shooting yourself in the foot.” Can Gingrich overcome this gaffe? It is doubtful.

Another example of shooting yourself in the foot can be placed on the teleprompter of President Obama’s Middle East speech in which he proposed that Israel return to the pre-1967 borders.

In his suggestion, Obama did what no other president has ever done: He took sides against the Israelis. The inference is that Israel captured territory to enlarge its country. The reality is that the annexation was strictly defensive.

The Golan Heights rise a couple of thousand feet above Galilee and provide an enemy a superior position from which to attack. This is exactly what Syria did in 1967 and might well do again if Israel relinquishes this area.

Before capturing the West Bank, Israel was narrow in that area and thus vulnerable to an onslaught that could cut the nation in two. Asking them to return this territory is like asking the U.S. to return Texas to Mexico.

To refresh your memory of the Six-Day War that changed those divisions, Syria and Egypt were determined to eliminate Israel once and for all. Israel fought back and won — in six days. These are a resilient people who have been pursued and persecuted throughout history from the pharaohs of Egypt to the Hitlers of Nazism. Yet Obama sided with its enemies.

The free world took notice of the horrors of the Auschwitzes of the mid-20th century and fought to end the anti-Semitism that is just as vile as racism. We thought we had succeeded, yet anti-Semitism exists on the same planet as racism. We must thus be constantly vigilant to forestall these evils.

Personally, the persistence of such thinking has always baffled me. I suspect this is because my favorite bosses have been Jewish and the creative people I most admire have been Jewish — the Rodgers and Hammersteins and Harold Arlens and Jerome Kerns and Gershwins. Not to mention Kirk Douglas and Billy Crystal and Douglas Fairbanks and George Burns.

Nor can we overlook sports figures like Hank Greenberg, Sandy Koufax and Max Baer. Or men of science like Albert Einstein and Paul Ehrlich and Robert Oppenheimer. The contrast between the ­accomplishments of Jews versus Muslims is almost a cliché. Yet Obama sided against the Israelis.

Israel’s neighbors in the Middle East have vowed to erase the Jewish nation from the face of the earth, using words like extermination and obliteration. Israel has never made those threats against those neighbors. Yet Obama took sides against the Israelis. Has he ­forgotten the Holocaust? Is he too busy playing golf and campaigning to recognize these people who took an arid wasteland and turned it into a fertile nation?

Barack Obama has shot himself in the foot as ­recklessly as Newt Gingrich. In addition to his siding against Israel is his flouting the 1973 War Powers Resolution that provides that the president can send U.S. armed forces into action only by authorization of Congress or in case of an attack upon the United States. This has even some Democrats irate. Maybe they should declare a “12th Commandment.”

Can the president recover from these self-inflicted wounds? Possibly. His defenders will argue that it was never his intention to take sides, that he was merely seeking a peaceful solution to an almost unsolvable problem. He is a smooth operator who still convinces millions of Americans that he speaks nothing but the truth.

Yet he took sides against Israel, one of our staunchest allies, and he appears to take his oath to protect our constitution lightly. We should remember these things when we enter the polls in November 2012.

Allan Jefferys, a former New York theater critic and newsman, lives in Pinehurst. Contact him at oldjeff@nc.rr.com.