The hush money was paid to Daniels in 2015 before the election to keep her mouth shut which was of course illegal. Apparently it worked because the public did not learn about the affair until after the election in 2018. It was not just $130,000 Trump paid hush money. He paid off a playboy model $150,000, I guess she did more for Trump than Daniels and a doorman, $30,000. How many more he paid off we will probably never be know.
However the amount of payments are irrelevant. Paying hush money to help win an election is illegal and has been for a long time.
My question is why should the city of New York turn a blind eye to Trump's payoffs when they have been prosecuting people for election payoffs for years? People you never heard of went to jail for doing a lot less than Trump. Even if Trump is convicted, he won't spend a day in jail. In fact, he will probably be able to turn his crime and prosecution into a badge of courage that will help get elected.