Total Guess Time:
Was it Owlman ???

Decent guess, but wrong.

Keeping with the theme:

Was it Ultaman ???

No, but good guess again!

"Ultaman" ? I meant "Ultraman". Sheesh.

Still wrong.

Was it "Lawyer Man" ??? Or his some-time partner, "ACLU" ???

As in real life the lawyer was the real villain. Seriously.

True. But pit him against another evil foe, "IRS Agent", and he may lose the battle big time. Even the Joker fears the IRS Agent.
Even in an episode of "Batman: TAS", The Joker says he would never go up against the IRS.

Yep. The Joker may be insane but he's not CRAZY.

Ultraa. Not the Multi- Alien one. Earth Prime guy?

Funny, I don't have a comic with that storyline in it, but I have an evidently later one that refers back to it. Hence vaguely familiar.

Aqhoffman is correct! And the lawyer was actually an alien hivemind using the case to distract the JLA.

Close to what my next guess would've been.

Okay. I have to come up with a question. Which member of the JLA had a serious jones on for Power Girl during the Satellite era of JLA/JSA teamups?

Firestorm!