 Former President Trump spoke with Ukrainian President Zelensky. CBS's Robert Costa tells us Zelensky congratulated him on becoming the GOP nominee and condemned Saturday's attempted assassination. This is potentially a significant exchange. Trump has long been wary of U.S. involvement in Ukraine, and President Biden has made it a keystone of his record. If Trump starts to build a rapport with Zelensky, it could quiet some concerns. CBS News Brief. I'm Stacey Lynn.