One thing Trump does well is that he makes some outrageous comment and then just waltzes onto the next one, leaving opponents trying to rebut what he just said while he is dumping another load. My advice to Biden, the DNC, and others is to stop doing that and turn the tables on him by making him defend himself against plausible accusations. The problem with denials is that just the act of denial makes people think there’s something to it. While he is responding to that accusation, you roll out another and then another. Make him play catchup.
So, you might start with an accusation, not at all farfetched, that Trump plans to eliminate the FDA. The ad would speak to a fairly primal fear among Americans. How do I know my food or the drugs I take are safe? The ad is so emotive and so darned easy to write that even I could do it. Then Trump will deny it. But people will wonder. While he is responding to that, another accusation. Trump is going to eliminate Social Security, a charge that has real credibility and scares the shit out of older voters. Then roll onto elimination of agricultural subsidies, another credible charge. You could just run the gamut of Federal Agencies like the EPA. But the key is to mount a rolling assault. Make Trump deny and deny and deny. Each denial will strip off a layer of credibility until he stands naked.