Tonight on The Last Word: The Biden campaign blasts Donald Trump's comments on Russia and NATO. Also, a neuroscientist discusses how to evaluate age and memory. Plus, Trump goes to the Supreme Court over his immunity claims. And Democrats hope to flip a seat held by George Santos. Professor Timothy Snyder, Charan Ranganath, Andrew Weissmann, and Rep. Daniel Goldman join Lawrence O'Donnell.

Tonight on The Last Word: Jack Smith urges the Supreme Court to act quickly on the Trump January 6 case. Also, President Biden says Trump's comments about NATO are "un-American." Plus, Pennsylvania Democrats retain a narrow majority in a House election. And the Kansas City Chiefs parade shooting falls on the six-year remembrance of the Parkland massacre. Simon Rosenberg, PA State Rep.-elect Jim Prokopiak, PA House Speaker Joanna McClinton, Rep. Abigail Spanberger, Neal Katyal, and David Hogg join Lawrence O'Donnell.