This is 100% correct, so we can rest assured that many national Dems will mess it up by enthusiastically endorsing and campaigning with him, only to be hit by the inevitable, even worse, oppo from the Collins campaign.
Bill Horton
The practical effect of the Platner nomination is that the Democrats should redouble their efforts in all of the other more winnable Senate races now, just hunker down for whatever's coming next about Platner, and try not to let the fallout hit other Dem races.