Mr. Trump is planning to attempt to deny birthright citizenship to the children of immigrants who are in the U.S. illegally, according to the incoming officials. The U.S. government has long interpreted the U.S. Constitution to mean that those born on American soil are citizens at birth, regardless of their parents' immigration status.

Trump's executive order interprets the law in his favor, but with lawsuits already pending, legal experts have been skeptical he'll succeed.

One of the many executive orders President Donald Trump signed on Monday included one to end birthright citizenship. Here's what to know about it and why lawsuits have already been filed.