What if in another country you marry two people could you move back to united states?

not without the correct visa

Polygamy marriages are illegal in the USA and won't be recognized, so the people you married in that other country wouldn't be recognized as spouses. Possibly one would but not both.

In the U.S. you can only be legally married to 1 person at a time (and most other countries too). the second wouldn't be legally recognized.

As far as the U.S., assuming you're a citizen, yes you can move back here. Your new spouse may or may not be able to join you, they would have to go through immigration like anyone else.

If you're not from the U.S., no... you also would need to go through immigration. Marrying a U.S. citizen doesn't guarantee you can live here. If you were deported, marrying a U.S. citizen doesn't void or go around being deported.

You can come back to the US, but only your first marriage will be legally recognised.

Moving back to the US wouldn't be prohibited. Having both marriages recognized as valid in the US is legally impossible.

yes. rather obviously, Barrick Obama, Sr. did it. Of course, the second "wife" won't be legally recognized as such in America where her "marriage" is illegal ....