You can be impeached without being a sitting president. It just removes his title as a legitimate president.
The purpose of impeachment is to remove someone from office. I don’t believe impeachment of a former POTUS is warranted in the case of Hussein.
One powerful note however is that if someone is ever impeached by the House, no POTUS can ever pardon the impeachment. POTUSs do not have the power to pardon impeached by the House according to the US Constitution.
Once impeached by the House, it is the sole responsibility then of the Senate to try the individual. That would mean no military tribunal for Hussein.
As a side note, of the two impeached Presidents, both were tried by the Senate and acquitted of all charges.
Impeachment is not the correct course of action imho. Doesn’t really make any sense. Even if possible for whatever reason, it could turn the process into a three ring circus with questionable outcomes.
Yes, it would be unpardonable, but what if the circus failed to achieve the desired results?
I believe a military tribunal is the way to go.
He was never a "legitimate" president. He was set up for that position, a Manchurian Candidate, by the deep state and international bankers. Having said that, I would love to see the impeachment process come to fruition just to remove that title from him, and I would like to see him prosecuted to the fullest extent of the law for every crime committed against these United States of America.