Bit of a tautology, isn't it? I thought a crime was anything that it was OK to prosecute someone for.

The issue here is that people went looking for a crime for almost a decade, singling out Trump in a deranged crusade. Bush levelled entire countries. Obama put the foundations of the global spying apparatus in place. Biden might be on the verge of igniting WWIII with the policies of escalation that the US is employing.

Then in that background, there is speculation that Trump is going to be arrested for something related to Stormy Daniels after the levels of effort put in to pinning something on him. The people who feel that is appropriate can't serious. Based on what we've seen of the Trump saga so far, this is probably abuse of process. If that level of effort was put into another politician, they'd be in jail too.