That's "penal", not "penile".

The penal battalions were units in Stalinist armies composed of convicts that were used on first-wave suicide missions, like clearing minefields or preliminary softening-up attacks on strongly defended enemy positions. Since he no longer has any hope of political office and already has the wrath of many of his own party on him for his arrogance and incompetence, he is free to take the casualties and flush out opponents, try out potentially disastrous ideas, draw enemy fire, and otherwise do dirty work that potentially more valuable Republicans might get hurt by. It's a role that used to be played by Limbaugh. He can say and do the things Republicans want to say and do, and spare the others from taking any heat for it.

The Republicans should beware. He's a loose cannon and will turn on his own kind if he feels threatened--like he did with Colin Powell.