LOL, this is not safe R and not even likely. Lean R is about right for the moment, as of Dec. '18. If a Dem prez is elected with at least the 2012 Obama margin, this seat should flip.
This, but Vilsack is a terrible candidate. He would be Strickland 2.0, just as Beebe would be Bredesen 2.0.
I wouldn't be mad if Beebe ran. In fact, I would welcome it. There is no chance that any Democrat will ever win a Senate seat in Arkansas in a Presidential year, but everyone would think "Beebe has a shot" and perhaps CCM could trick Republicans into wasting cash there.