Philadelphia lawyer

Etymology
Possibly derived from Andrew Hamilton's skillful defense of John Peter Zenger in 1735, though, as the phrase is not attested until 1788, this is uncertain.

Noun

 * 1)  A clever, crafty, or otherwise extremely adroit practitioner of law.

Usage notes

 * Of something extremely hard to understand or resolve, it may be said that it would (or is enough to) puzzle a Philadelphia lawyer.