Going into the Oct. 1 vice presidential debate, Gov. Tim Walz (D-MN) seemed to have something of a lead on his Republican counterpart, Sen. J.D. Vance (R-OH). The Minnesotan came out slightly ahead in favorability polls, whereas the Ohio senator is more than 10 points underwater. It seems that Democrats’ efforts to label Vance “weird” and extreme are working to at least some extent.  But Walz, like his running mate, Vice President Kamala Harris, remains in many ways a total cipher to voters. From his perch in St. Paul, he has advanced one of the most progressive agendas of any state governor in recent memory, but he has somehow managed to build a reputation as some kind of a dispositional centrist. If Republicans want to overcome his folksy Midwestern appeal, they will have to reveal...