When Trump was pressing Biden about any police unions supporting him, Biden should have just laughed/snickered and said that now it seems that Trump is a union supporter.
Then go on to explain that before unions, Americans workers were treated and paid very poorly in America, And when workers tried to organize and form unions they were routinely beaten up by hired security thugs and/or local police. After FDR (it's okay to mention Dem heroes) implemented labor reform encouraging unionization, workers were treated and paid better, had more job stability and rights, better safety and working conditions. There was an unprecedented middle class boom in the USA when unions flourished. And then after unions were attacked by Reagan and subsequently marginalized and dismantled by the GOP and Big Business over the past 4 decades, American workers have again gone to being underpaid with fewer rights and benefits, and the middle class has suffered. And the country is worse off for it.
Conclusion: we're a better nation when the middle class is strong and unions play a major part in that. While for the past 40 years the GOP has attacked and undermined unions and hurt the American middle class, promoting policies that enrich the rich and screw over the working class.
He could continue that the GOP is against worker's rights, against better pay for workers (mention the minimum wage) and such, but really that's enough.
Nothing wrong with giving a little history lesson on unions and the middle class. The kind of thing Donald Trump cannot manage.
Anyway, once Trump mentions unions, it's such an easy opening to get across Dem economic policies and support for the middle class.
I really would love to see Hillary debate this hugely failed Trump.
She'd have so many facts at her command to just shred this guy. And she's smart on her feet and tough.