system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can the President reveal that he wants to strike Syria (or anywhere else) in a press conference and not expect that to affect the effectiveness of the operation?

Wouldn't something like this allow the "enemy" to prepare, etc?

edit: Thanks everyone! TIL that military intelligence is way more complicated than I thought.
gpt
The revelation is the point. By stating that this is a plan in the works, you alter the diplomatic landscape. The threat of US strikes may embolden Assad's enemies, for example. 

Also, there's not much most countries can do in a practical sense to prepare against United States airstrikes. The US's conventional ability is at least a generation ahead of most of the rest of the world.

Third, countries are sorta big. By discussing it in geostrategic terms ("we're going to bomb Syria") as opposed to theater-strategic or tactical ones ("we're going to bomb this particular building in Damascus"), you really don't give much away.

So you get a few benefits from discussing it openly.