[x]

We don’t call people who come to the U.S. via the legal channels “legal aliens”...

The law distinguishes between "resident aliens" and "non-resident aliens."

Both could be called "legal aliens," rather than "illegal aliens," also a term from the law books.

I notice though, that a lot of sources that don't go with the "undocumented workers" euphemism are using "illegal immigrants," rather than "illegal aliens."

[MileHi]

Good point. Besides immigrant, I could have added tourist or visitor I suppose.