Welcome back to Trump Watch. The president’s decision to declared a national emergency Friday in order to construct a wall on the U.S.-Mexico border is lighting up social media. We’re taking a look at one interesting angle to keep an eye on in the looming litigation fight over Trump’s wall.

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U.S. President Donald Trump speaks in the Rose Garden at the White House in Washington, D.C., on Friday, Feb. 15, 2019. Photo: Al Drago/Bloomberg

A National Emergency