The land was free and perfect for farming, if settlers survived the journey to Oregon the land was all theirs. But not only did the US like it, Britain and Russia also liked it. So the US told people to move there ASAP so it would officially be claimed by America.
In United States v. Nixon, the Supreme Court’s ruling made it clear that (A. the executive branch is the most powerful branch, but the president must still obey the law.)
