Immigration law has many quirky rules. 

In some cases, this is because laws and customs in other countries do not match up with laws and customs in the United States. 

Take Polygamy. 

Based on religious and cultural beliefs, Polygamy is a custom that has been practiced in over 81% of societies across the world.  

Yet, immigration law treats Polygamy the same as Bigamy, the U.S. crime of being married to more than one spouse at one time, often based on deception.

Recommended Links For More Information:

Polygamy vs Bigamy: A Battle Over Cultural And Religious Imperalism

Trapped In The Politics Of The 1960s: Immigrant Relative Visas