Reagan had another rule, his Eleventh Commandment: “Never speak ill of another Republican.”
Anybody listening?
In all the writing I read on and by Reagan (a lot) I never saw him advocate supporting open liberals. The 11th isn’t a suicide pact because some jackass has an R attached with velcro.
If you want to take the 11th out to extremes, would Bill clinton suddenly be off limits if he called himself R ? Nope. And neither are the Mitch types.