Earlier quoted context omitted.
> I'm American [...] I may be missing context. You are missing context: look up "Parliamentary Privilege" and "Parliamentary Sovereignty" which do not have US equivalents. The "invitation" was effectively a subpoena.
Didn't the fact that is not a UK citizen also basically safe him from being dragged to Parliament by the police? Im pretty sure, if you are an UK citizen and they summon you, they will eventually just grab you and put yourself in front of Parliament.
A question for any legal scholars out there: the seizure of the documents would be contempt of court in the US, could it not? The person who was threatened with arrest has the defense of duress, so could the US court charge the MPs who ordered the seizure? I don't think the UK would extradite, but if the MPs were to visit the US without immunity, could they be arrested for violating US law (even though their actions are apparently within their rights under UK law)?