What if they discover definitive evidence of active single-celled martian life, but there's disagreement how "life" is defined vs an abiotic chemical system?
https://kalshi-public-docs.s3.amazonaws.com/contract_terms/A...
It's far more likely that any official "disclosure" is part of some kind of psyop than it is that aliens are actually here on Earth. I'm reminded of that old Outer Limits episode where the government surgically altered a soldier to look like an alien in order to fake an alien invasion, so that humanity would unite under a common enemy (and presumably a common American imperialist regime.) Of course there are tons of conspiracy theories along these lines (Blue Beam) and I would have written it all off as insane until a few years ago. Now I don't doubt that they would try and I don't doubt people would fall for it. Even when it was proven a hoax, people would still believe it.
To draft new executive powers with hidden budget discretions.
Post 9/11 everyone serious in the global intelligence game learned to bank on “debt cards.” These spend right off the national debt.
And there are those patentable discoveries looted from the ultra secret enclaves.
Besides, the world would not unite in this way for the sides as you have described them. Man is our enemy.