A bipartisan bill to secure the Robert Mueller investigation has almost certain majority support in the Senate, as Greg Sargent reports. Judiciary Committee Chairman Chuck Grassley appears to be moving toward considering the bill. Is this, as Sargent proposes, a big test for whether Grassley and Majority Leader Mitch McConnell really mean it when they say that President Donald Trump should allow the investigation to proceed unimpeded? Well, sort of.