Here's the thing: Broder is only interested in the theatrics of independence -- whether it be Lieberman's claim to represent mainstream opinion on Iraq, or McCain's elaborate showdown with the White House on torture. At bottom he just wants to tell a story -- one which implicitly flatters himself and a few chosen fellow warriors as heroically fending off extremism on both sides -- and the theatrics of independence offered by Lieberman and McCain give him the dramatic material he needs to tell it. Reality and real-world impact be damned.
This is right. People like Broder and Klein see politics entirely as piece of theater which exists to entertain and and please them. It is an ongoing show, and they are theater critics all-too-interested in the quality of the buffet put out for the press. As consumate insiders they are psychotically obsessed with the notion that they are actually outsiders, and so they are pleased most of all by the characters who are insiders-posing-as-outsiders who allow them to nurture this particular conceit.
These are damaged people.