The gist of it is, the hush money payments were covered up by filing false business records claiming it was for "lawyer's fees". That's the first issue. The second issue is that it can be considered an improper campaign contribution because it was to benefit the campaign.

In order for it to be a felony, you need to connect the two together. Otherwise it's a misdemeanour.

In terms of it being a "weak case", I would just say let's wait to see what the prosecutors' argument is - this will be released when the indictment is unsealed on Thursday. It's a document-heavy case. There is a witness who carried out the crime (Michael Cohen), and other witnesses as well. I would also posit that the prosecutors, and a grand jury (who unanimously voted to indict) would not take the unprecedented step to charge a former President unless they thought there was a strong case.

So, let's just wait and see.