The Situation Room With Wolf Blitzer

Democrats take big step toward possible impeachment by suing for secret grand jury information from Mueller report; Trump on new impeachment threats: Dems "Want to go fishing"; Trump lashes out at Fox News poll showing him losing to Joe Biden and Bernie Sanders; As CNN debate near, Biden previews aggressive approach while Harris says she will be polite; New poll shows Biden far ahead of other democrats; North Korea boasts of missile firings as Trump downplays threat via Knit