John Milius' Commentary
In the audio commentary, when Briggs reveals himself as one of the Death Squad and pulls a gun on Harry in the car, John Milius says Harry isn't worried because "he knows this guy is just a wimp liberal." Um, what? In the Dirty Harry universe (at least according to Milius), liberals are actively trying to protect criminals and thwart true justice, which is why Milius keeps saying we need vigilante cops like Harry (more on this below).
Doesn't Briggs being a member of the Death Squad - nay, its mastermind and creator! - make him as far from what these movies consider a "liberal" as possible? If he were a liberal he'd be opposing the Death Squad, not supporting it! And yet even after he's revealed as being pro-vigilante, Milius keeps calling Briggs a "whiny liberal."
John Milius also bemoans the state of the American justice system, and says we need vigilante cops (his words not mine) like Harry. Except Harry isn't a vigilante.
What sets him apart from Briggs and the Death Squad (and what they - and Milius - can't seem to understand) is that Harry kills suspects while they're committing crimes. Usually while they're fleeing capture, endangering nearby people, or attacking him directly, and, more than once, he has shot to wound and brought bad guys in alive.
He does what it takes to get the job done, but at the end of the day, theres only so far he's prepared to go. He doesn't hunt crooks down to their homes and murder them in cold blood after they've had their day in court because he doesn't like the verdict (and what's more, he himself says as much).
So he isn't a vigilante. He operates as much as he can within the law, sometimes a little outside it, but there's a line Harry almost never crosses. The only thing he's guilty of is arguably excessive force.
"I mean, really, how many times will you look under Jabba's manboobs?"