The Trump administration appealed a Washington federal judge’s order blocking the president’s executive order (EO) on birthright citizenship from being enforced, hours after the judge scolded the administration for using the EO for personal and political gains.

The hearing comes after a federal judge in Seattle blocked the order and decried the administration’s treatment of the Constitution.

President Trump is seeking to end birthright citizenship in the United States. What is it, which other countries apply the policy and who would be affected by the order?