California Attorney General Xavier Becerra is preparing to file a lawsuit challenging President Donald Trump's national emergency declaration, Becerra told CNN's Kate Bolduan Monday.

Sixteen states filed a lawsuit on Monday challenging President Donald Trump's national emergency declaration for the southern border.

CNN's Anderson Cooper questions President Trump's urgency and actions after declaring a national emergency to fund a wall on the southern border.

President Donald Trump's allies are mounting a stiff defense of his declaration of a national emergency amid increasing signs that the biggest threat to his border wall now comes not from Congress, but the courts.

New Mexico attorney general Hector Balderas says he is joining several other states in a lawsuit to sue the Trump administration over President Trump declaring a national emergency to secure funding for a border wall.