The right to travel has long been recognized by the courts as inherent in our constitutional concepts of personal liberty...Because that right is fundamental, the [U.S. Supreme] Court reasoned, "any classification which serves to penalize the exercise of that right, unless shown to be necessary to promote a compelling government interest, is unconstitutional."

Freedom of movement, at home and abroad, is important for job and business opportunities -- for cultural, political, and social activities -- for all the commingling which gregarious man enjoys. Those with the right of free movement use it at times for mischievous purposes. But that is true of many liberties we enjoy. We nevertheless place our faith in them, and against restraint, knowing that the risk of abusing liberty so as to give rise to punishable conduct is part of the price we pay for this free society. Freedom of movement is kin to the right of assembly and to the right of association.… This freedom of movement is the very essence of our free society, setting us apart. Like the right of assembly and the right of association, it often makes all other rights meaningful….Once the right to travel is curtailed, all other rights suffer, just as when curfew or home detention is placed on a person.