On the incongruence between the visa-free travel for U.S. citizens to the EU and the obligation for a VISA imposed on citizens of some EU Member States when travelling to the U.S. 

Citizens of fFour EU Member States (Bulgaria, Croatia, Cyprus and Romania) still need to obtain a VISA to travel to the U.S., since they have not yet entered the US Visa Waiver Program. However, all Member States from the EU are compelled to allow U.S. citizens a 90 days stay in their territory without any restriction. The petitioner claims that this violates EU law and calls for a review of practices imposing a visa to U.S. nationals as well in view of obtaining their visa for a 90 days stay permission, until the four affected Member States are accepted to be part of the US Visa Waiver Program.