@cbsnews: President Trump has vowed to make “a really long speech” on the Fourth of July as he speaks on the National Mall to commemorate the nation’s 250th birthday, even as a major heat wave traps the capital region and more than half of the United States under a heat dome through the holiday weekend. “I’m going to make a really long speech just to show that I can do anything,” Trump said during his remarks at the opening ceremony for the Theodore Roosevelt Presidential Library in North Dakota on Wednesday. Highs of over 100 degrees are expected on Saturday in Washington, D.C., which would top the capital's highest recorded temperature for that date, 100 degrees, set in 1919. #july4 #trump #heat #weather #dc