Lawrence: Trump's the first president in history to say he's 'too busy' to explain a war he's waging

Tonight on The Last Word: The Senate advances a bill to limit Donald Trump’s Iran war powers. Also, Sen. Sheldon Whitehouse slams Trump’s “cop beaters' slush fund.” And the Justice Department nixes audits for Trump, his family, and his businesses. Sen. Gary Peters, Sen. Sheldon Whitehouse, Ali Velshi, and Andrew Weissmann join Lawrence O’Donnell.