A federal judge has temporarily blocked President Donald Trump’s executive order ending the constitutional guarantee of birthright citizenship regardless of the parents’ immigration status.

A federal judge Thursday blocked President Donald Trump’s executive order outlawing birthright citizenship —the policy automatically giving citizenship to anyone born in the U.S.—and declared it “blatantly unconstitutional,” as legal experts widely believe the president does not have the power to change the policy on his own.

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.