It is quite obviously completely illegal, and you can look at the search warrant (indicating a judge agreed there was probable cause) for the specific laws. I copy/pasted a few below for you. Whether all or some of those laws are constitutional and will stand up in court can change year by year. I strongly, strongly suspect that no judge is going to strike down the government's ability to restrict people from collecting and disseminating information on secret military installations. It is objectively true that these installations, their secrecy (and this one installation and its secrecy in particular) have been instrumental to the federal government's ability to carry out its obligations over the past several decades.
Arresting people for openly breaking the law is a perfectly valid component of "securing their stuff." In fact that is precisely how almost everything in our society is actually secured: by threat of law.
I stand corrected. 18 USC 796 I can understand, but 18 USC 795 and 18 USC 797 surprise me. I would have thought such laws were restricted to military personnel. Civilians sketching or photographing from public space I would have thought would be legal.
You can’t spy on police and government buildings because they’re not sensitive.
They are largely meant to operate in the public eye. Some weapon development programs aren’t (thus they are secret).
Please note: If you pull up to the gates of CIA with a zoom lens and start taking photos of their doors and windows, you will also have a very bad time, despite the fact that both inside and outside the gates are public land.
My point is I don't think it should be illegal to openly photograph anything visible from public land. It should be the government's responsibility to secure and hide their land without criminalizing interested members of the public from taking photos and observing what they are doing.
It's the equivalent of sunbathing naked on your front lawn and getting angry that someone is taking photos.
FWIW I get (and agree with) the philosophical thrust of your argument here, but in reality it doesn’t make any sense.
The world you’re describing is one where government facilities have to all be in profoundly challenging places to operate facilities in, and even once you do that, a Chinese or Russian national is 100% within their rights to pull up a tent right alongside it, put a camera up on a 300 foot tower, and surveil the site 24/7.
Under the Constitution, anyone in the US has the right to do what you’ve described, and so they have the right to do what I’ve described too.
I get what you are saying also, and kind of understand it.
I think I would just prefer if rather than making it illegal to photograph a base that happens to be visible, actual treason or espionage should be the only things which are illegal, and the government needs to prove that.
It might make things harder on the government, but I think it is fundamentally more fair.
If you film stuff from public space, you are not breaking any law.
The onus is on the government to secure their stuff, not punish people taking photos from public lands.