Speaks to the same lack of clarity on my part.
Was referencing Muslims in general, not USA law.
Mormons have the same religious law. So if a Mormon was living in Saudi Arabia, Egypt on Turkey he could have more than on wife.
Strange there are no religions where woman are allowed more than on husband though such a situation existed in the past, or in certain cultures.
The Pandava Princes [5 brothers] of India are said to have shared one wife.