Tonight on The Last Word: Talking Points Memo obtains Mark Meadows's texts about Rudy Giuliani. Also, mass shooting survivors urge Congress to act on guns. Plus, Florida Gov. Ron DeSantis forms a panel of anti-vaxxers to counter the CDC. And researchers announce an historic clean energy milestone. Joyce Vance, Paul Butler, Stuart Stevens, Rep. Ayanna Pressley, Brandon Wolf, Florida State Sen. Tina Polsky, Dr. Michael Haller and Andrea Kritcher join Lawrence O'Donnell.