Does enforcement of US borders and prosecution of trespassers have negative karmic consequences for all US citizens as they are indirectly linked to government actions?

This is very much the case and is something to consider. You are not free of responsibility through choosing inaction. Failing to vote, failing to protest, failing to demonstrate and take action to engage with public officials to register complaints, failure to support and be active advocates and supporters of potential representatives who share your views is making choices. To be resigned to the current way of things and to settle for less, this will have karmic consequences, so it is true of everything done by your government, including acts of war, it is all on your head. Whenever people are imprisoned unjustly, suffer needlessly, are deprived of the basic necessities of life when that can easily be arranged, especially at a minimum level for subsistence, these are inexcusable acts and will be felt by each and every person in that chain of responsibility in some way at some time in the future. Karma will see to this and it is inevitable. The idea of war putting people in harm's way is a perfect illustration. It is only that people do not see, it works both ways and spreads in all directions. The burden of war falls as heavily on the victor as on the vanquished.