4th Amendment case
The Supremes just decided Virginia v. Moore. Defendant was caught driving on a suspended license. State law provided that he be given a summons, rather than arrested, for that. Officers instead arrested him, and a search incident to arrest uncovered drugs.
The Court, per Scalia, holds that a violation of such a statute does not a 4th Amendment violation make. Police had probable cause and the arrest was not "unreasonable." Justice Ginsburg concurs, suggesting it is a little closer historical case than the majority opinion suggests.