What does “under oath” mean to these people?
You are asking the correct question. They will lie because our “oath” has no value in their system of government. Nothing new will come of this, unless they can be proved to have lied “under oath.” Then they may have to give a carp.
Nothing.
But that is neither unexpected nor new ; Taqiyah.
What is mind boggling is that this, a well known tactic of islam in its militant form, is grasped by any casual reader of history, islam and its blood-dripping history. Yet it eludes all our national security and police agencies, we won't even attempt to try to explain why Hussein and his Justice Department seem to be on the payroll of the "muslim brotherhood."
There is a further policy that can be opnly described as incompetence or treason. Citizenship oaths are meaningless to them, and when demonstrated fraud is obvious, there appears to be no mechanism to revoke fraudulently obtained citizenship!
Once that fact is in play, the citizen-enemy combatant issue becomes moot.
Strip a terrorist's citizenship obtained by perjury, then treat him/her as what they are : terrorist enemies on a mission.