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.

➤➤ Would you like to receive Trump Watch as an email? Sign up here.

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

President Donald Trump's declaration of a national emergency, a move designed to build a wall along the U.S.-Mexico border and sign a budget deal that would head off a second government shutdown, sparked an immediate outcry and raised the potential for a firestorm of lawsuits.

Trump will dedicate about $8 billion for construction of a border wall. Much of that money would come from diverting funds appropriated for other purposes, including the Defense Department's military construction projects, to finally deliver on Trump's campaign promise of a wall.

Groups have already vowed litigation, including Protect Democracy and the Niskanen Center, which said Thursday they have prepared a lawsuit on behalf of El Paso County, and the Border Network for Human Rights. California Attorney General Xavier Becerra, a frequent legal foe of the Trump administration, tweetedThursday that if the president declared an emergency, “we won't only call his bluff, we will do what we must to hold him accountable. No one is above the law.”