Not foolish. It would be a smoking gun to end Trump as soon as it is released. Why wait?? Would we really need an investigation if someone is caught red-handed? Comey should've ended it the moment Trump said it. He didn't. That's on him. Now to bring it up after he gets fired says "disgruntled worker" not "hero". It lacks credibility even more now that he testified under oath to congress that he does things outside of the chain of command without informing his bosses if he feels not inclined to do so. And still all this is only allegations. Like middle school all over again with the he said she said. 
"Tapes" - Scotch tape, duct tape, video tape, two way tape, packing tape, masking tape... what "Tapes"? Trump is smarter than people gives him credit. He tweets better there aren't "Tapes" and now everyone is looking for paper and tape. Crazy!