Actually, my friend, there are standing orders when lethal force is authorized. To prevent the access to a nuclear weapon or significant quantities of special nuclear material is one. While it is a good thing that the guards at Oak Ridge who did not shoot the nun who broke in, they were fired for failing to do their job.
Protecting certain categories of classified levels of information at the top secret compartmented level is another. Act like you are trying to break into a SCIF and you will be rapidly subdued by whatever means are required. In a rapidly escalating order, you will voluntarily submit - grinding your nose into the pavement with your obviously empty hands on your head, or you will be involuntarily subdued or incapacitated or you will be dead, but you will be subdued. We don't need to speculate on what kinds of information is kept under wraps at area 51 since we already know that the F117 and B2 were tested there when they were black programs.
I didn’t say their were no ROE for use of lethal force. I said the US military will not open fire on a bunch of illegals crossing the border. We need too use less-than-lethal force to stop them from stepping into the country and short stop all this deportation/detention BS.