It would be very surprising if they lost on this, but I question what exactly winning would truly accomplish? The concept of a foreign legal enforcement agency appearing in a US court seems very strange to me.

Foreign gov't agency can still create them a bunch of problems, I think, even if not directly in the US. So they want to bring this case into political dimension. If succeeded it would mean UK harasses US entity on American soil for exercising constitutional rights as proven legally. In turn it would create grounds to engage US State Dept into the affair.

Not gonna spend PACERbux on this to find out, but not sure how they’re arguing there’s an actual case or controversy to rule on, since no one’s trying to domesticate a judgment against them in the US. This is just an attempt to preemptively weaponize the US courts against the UK government, good chance it gets bounced for lack of jurisdiction.