I remember when Ronald Reagan invoked what he called the “11th Commandment,” which decreed that Republicans never should speak ill of other Republicans.

Some of today’s Republicans — self-professed devotees of the Gipper — are committing a form of political sacrilege. They’re targeting fellow Republicans with abandon.

The latest of them is one Liz Cheney, daughter of former Vice President Dick Cheney, who wants to run for the U.S. Senate seat in Wyoming against, that’s right, Sen. Mike Enzi, a Republican incumbent with a 92 percent rating from the American Conservative Union.

Seems that Enzi’s major “sin” has been his willingness to work with Democrats in the Senate. Cheney’s announcement of her candidacy declares she will never compromise. She’s going to stand by her principles, by golly, no matter what.

Enzi said he “thought we were friends” when describing his relationship with Cheney. Apparently not.

In another interesting twist to this budding campaign, Chris Mathews of MSNBC noted today that Liz Cheney has never actually lived in Wyoming. She went to high school in Washington, where she lived with her parents and younger sister. Cheney recently moved to resort community of Jackson Hole, in western Wyoming. But as Howard Fineman, also of MSNBC, noted, that is like “someone moving to the Hamptons and then claiming to know all about New York state.”

As for the 11th Commandment, Cheney is just the latest GOP hopeful to throw President Reagan’s mandate into the dumper. Utah GOP Sen. Bob Bennett got “primaried” out of office by another Republican. So did Republican Sen. Dick Lugar of Indiana. Those men had this habit also of working with Democrats to craft legislation, to get things done for the good of the country.

As the Republican Party continues fighting among itself, though, it is embarking on a suicide mission.

Somewhere, the Gipper is wishing he could come back and talk sense into his ideological descendants.