Jim Geraghty of National Review and Greg Corombos of Radio America welcome Arizona Sen. John McCain back to Capitol Hill despite the grim diagnosis he received last week, and are happy that Republicans now have a full roster as the health care debate continues. They also bemoan President Trump's continued use of Twitter to attack Attorney General Jeff Sessions for being "weak" in failing to investigate Hillary Clinton over her emails and alleged collusion with Ukraine during the 2016 campaign. And they analyze a surprising new Michigan poll showing rock star Kid Rock leading incumbent Sen. Debbie Stabenow.