This week on Face the Nation, the fragile detente between the US and Iran is disrupted and tensions over the war with Iran explode between President Trump and the Republican Senator he worked to defeat. Following a Capitol Hill shouting match between President Trump and Louisiana Republican Bill Cassidy over the Senator's vote against the war with Iran, we spoke exclusively with Cassidy about that exchange, his relationship with the President and his thoughts on the administration's health policy agenda as Cassidy wraps up his Senate career. We also speak to Virginia Senator Tim Kaine about the shift of the Democratic party to the left and check in on all the other news of the week. Finally, the Supreme Court is on the verge of wrapping up this session, for some analysis on last week's key decisions and a look ahead to those last few cases, we turn to chief legal correspondent Jan Crawford.