President Donald Trump on Monday declared a national emergency over what he called “an invasion” at the U.S.–Mexico border. The White House on Monday night said in a proclamation that the Trump administration has a legal basis for the actions because the level of illegal immigration, drug trafficking, and criminal activity amounts to “an invasion under Article IV, Section 4 of the Constitution of the United States.” “I have determined that the current state of the southern border reveals that the Federal Government has failed in fulfilling this obligation to the States and hereby declare that an invasion is ongoing at the southern border, which requires the Federal Government to take measures to fulfill its obligation to the States,” Trump said in the proclamation….