https://en.wikipedia.org/wiki/Freedom_of_movement_under_Unit...
https://en.wikipedia.org/wiki/Saenz_v._Roe
> Justice Stevens, writing for the majority, found that although the "right to travel" was not explicitly mentioned in the Constitution, the concept was "firmly embedded in our jurisprudence."
As evidence of how these can be so easily abused, I present that time the government prevented an American citizen from entering the country to testify in a trial involving her mother against the Government about being on the No Fly list!: https://www.techdirt.com/articles/20131208/00164525497/witne... or https://papersplease.org/wp/2013/12/07/no-fly-trial-day-5-pa... or https://www.courthousenews.com/government-secrecy-vexes-judg...