An appellate lawyer doesn't argue at trial over the facts of a case but over matters of legal procedure, jurisdiction and the interpretation of statutes or the Constitution.
In theory, at least, this is rare air, briefs written in isolation and arguments presented before a three-judge panel, untainted by the hyperbole of a jury trial.
Which is not to say it's nice.
``You're saying the other guy's argument is stupid, it stinks. You have to be forceful and back that up.''
It is, Perwin said, ``exactly like debating. Like I haven't stopped debating since my first year of high school, in 1963.''
He had a mild existential crisis four years ago. He had had one 15 years ago, which he thought had been resolved after he called up his best friend, a man he'd barely seen in years, and convinced him to go on a cattle drive in Montana, something they still do yearly.
This time felt more serious. He wasn't sure if he was doing a good job at living.
``I'd been doing the same thing for 22 years, driving to the same place every morning, hanging out with the same people.''
Maybe he should have stayed in Washington. He knew people there doing neat things with their lives. Maybe he shouldn't be a lawyer at all. But he was no cowboy.
Perwin quit his firm and went into business for himself, sinking some money into the DuPont building office, fixing it up with marble and old wood and little statues of horses.
He has one employee, a legal secretary with superhuman organizational skills.
Some clients followed him from Podhurst, and new ones have come: Ecuadorean shrimp farmers suing DuPont over alleged pesticide runoff, the drivers of Florida suing the government of Florida over selling license information to telemarketers, the government of Belize, locked in an abstruse high-stakes battle over its telecommunications industry.
When business is good, it's great. When it's not, there's no one to fall back on.
''I'm working like crazy,'' Perwin said. ``It's tough when you're working on your own -- you don't ever want to say no, because you don't know when the next case is coming in. I'm working day and night . . . I don't think I'll ever stop. I don't know what I would do.''