Lawrence: What are Donald Trump's deranged social media posts if not evidence of insanity?

Tonight on The Last Word: Trump's Iran war continues to make life unaffordable for Americans. Plus, Trump threatens to stop the sale of Canadian Bombardier jets in the U.S. And the DOJ charges ICE officer Christian Castro for lying to FBI about Minnesota shooting. Sen. Peter Welch, Adam Hamilton, and Mary Moriarty join Lawrence O'Donnell on The Last Word.