John Steinbeck said this quote

Once California belonged to Mexico and its land to Mexicans; and a horde of tattered feverish Americans poured in. And such was their hunger for land that they took the land, stole Sutter's land, Guerrero' s land, took the grants and broke them up and growled and quarreled over them, those frantic hungry men; and they guarded with guns the land they had stolen. They put up houses and barns, they turned the earth and planted crops. And these things were possession, and possession was ownership.The Mexicans were weak and fed. They could not resist, because they wanted nothing in the world as frantically as the Americans wanted land.