Very likely a Republican pickup, unless they completely screw up and nominate a Roy-Moore-tier candidate.
Even if Beshear continues to ride on high approval ratings, these usually aren't transferable to their second-in-command when it comes to winning the next open election.
Exactly this.
Case in point, Mike Cooney.
I thought of him as well. The same applies to the presidential level: Nixon in 1960 and Al Gore in 2000 should have easily won given the outgoing president's popularity, Clinton in 2016 to a lesser extent. Only in 1988 it worked, but Dukakis was a weak candidate running an atrocious campaign.
