Here's a guide to what birthright citizenship is, what happens if Trump's order ends it, and what comes next after lawsuits were filed.

A second federal judge has issued an order blocking Donald Trump's administration from implementing his plan to curtail U.S. birthright citizenship, saying no court in the United States has ever endorsed the Republican president's interpretation of the Constitution.

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.