(I'm a lawyer licensed in 3 states, previously 4 :P) It is definitely illegal in various jurisdictions, and even criminal in many. It's also generally viewed

(I'm a lawyer licensed in 3 states, previously 4 :P) It is definitely illegal in various jurisdictions, and even criminal in many. It's also generally viewed to be no longer federally constitutional since the late 60's due to various supreme court decisions. As a result, most states have struck the laws down over time or repealed them (wikipedia has a map somewhere of this), so you generally only see it as a plea bargaining anymore. IE people will plead to adultery instead of a greater crime. (Yes, it's as weird as it sounds)