REYNOLDS v. UNITED STATES. SUPREME COURT OF THE UNITED STATES 98 U.S. 145 OCTOBER, 1878, Term
The SC said the religion could not be used to justify polygamy, and that historically our European heritage had never found the practice acceptable.
Because we as a society don't like it, just like we don't like gay marriage.
Societies should have the right to decide things like polygamy and gay marriage. Now if certain judges get their way, we will have it forced upon us.
One thing is for sure, if we get gay marriage, we will also get polygamy.
“Why is polygamy illegal?”
Same reason sex with goats is illegal.
Uh... because it's again st the law?
You might mean, "Why was polygamy MADE illegal?"