Of course that doesn't happen often (if ever) with retirees but Reserves...National Guard...it does today.IIRC it seldom happened during Vietnam but things have changed.
This mission of the militia is 3-fold, as specified in the US Constitution. Invasion, rebellion, and enforce laws of the states. None of that mission involves overseas operations. No could the militia perform such duties overseas.
Furthermore, service is compulsory for males; the US Constitution doesn’t know anything about a “reserve militia” or “unorganized militia.” It is the only institution that is necessary for a free state. Not Congress, the Judiciary, the Executive, or any other organization is cited as necessary.
So the Dick Act of 1906 and the proceeding NDAA are unconstitutional on their face.
Yet no one challenged the militia being essentially rolled up into a modified version of the US Army reserve. We lost the ability to deal with what confronts us today, because we don’t know our Constitution, nor history.
If we followed the Constitution, illegal immigration, and unsecured borders would be solved over a weekend. Not to mention all the other agencies that were created after the 1906 debacle, to fill the void.
Dr Edwin Vieira’s book “Constitutional Homeland Security” is a resource. As is his video “Principles of a Constitutional Militia.”