This could end up being a problem for Trump as Pecker has been a long time friend and associate of Trump who recently agreed to testify regarding the information he had regarding Trump's escapades with the playmate. The thing is that when he agreed to testify he signed a 3-year agreement that he would "not do anything criminal". Blackmail is considered criminal behavior. If he did, the agreement was null and void and everything he gave the government and that was covered by the agreement could be used against him.
As such, and possibly looking at a jail sentence, he could give the government a lot more dirt on Trump. Remember that this is the man that stated clearly that
he had a lot of information on Trump from all the years they were friends and worked together.
The old adage about "Show me who your friends are and I will show you who you are" applies to Trump in a big way. With close friends such as Pecker, Cohen, and Stone and the picking people for his cabinet or as advisers such as Manafort, Flynn, Gates, Pruitt, Price, and Porter, it certainly seems that Trump is choosing people that have no regard for the law.
And this is our President?