Whether the Spanish claimed it legally or illegally in the 1500’s, Mexico threw them out in 1821. Then sold it to us in 1848. Mexico if it had a legitimate claim to California only possessed it 27 years.
Many of the Mexicans in Texas and California territory had reached out to the U.S. for protection from their own government from Indians and other ruthless Mexicans.
Was it there's to sell? Did they obtain it legally ? Didn't the Mexican citizens that lived in those territories ask for protection?
The versions of facts on this subject vary in different books and even here on FR. Does anyone know what was Fake News surrounding the Treaty of Hildago or truth on who stole what ?
It’s a moot point. We’ve controlled the territory for well over a century. Whether it was obtained “legally” or “illegally”, it’s ours now, unless Mexico can muster the force to take it back.