Re: marriage for immigration
Polygamy is illegal in the U.S. It doesn’t matter if the first wife gives permission. If a man has a wife (outside or inside the U.S.), marries a 2nd woman in the U.S. and applies for immigration through the 2nd wife, he will be charged with immigration fraud if USCIS finds out that he’s already married. Not only will the application be denied, if I remember correctly, being charged with immigration fraud carries a lifetime ban from the U.S.