Under what authority would POTUS have to mandate and enforce a national lockdown? It's different for the governors, who generally have broad police powers. There are places where POTUS could act, such as airports and whatever areas and facilities that are under federal jurisdiction. A good portion of the country has already been under lockdown once and we're probably going to need another, but it will be authorized and enforced by the governors (not to mention we'll be facing collapse of the healthcare system if it has to wait for January 20th).
It's disheartening that we have to be re-imposing restrictions, and potentially heading into a renewed series of localized shutdowns, at this juncture in the pandemic. It's as if nothing has changed since March, and everything has gotten worse. As for political implications, it's possible that coronavirus fatigue may be having an effect on the election as we head into the final days. But I'll wait until Election Night to make judgment on that.
Who would said fatigue favor?