If what you say is true, then Delay can appeal and win.
You can’t be tried for a crime which wasn’t a crime when you did it.
Delay did launder funds in 2002. He conferred with several attorneys who determined that this type of money shifting was legal at the time. The type of money laundering he did was made illegal in 2005. Then he was put on trial for this. Contrast this case with Charlie Rangel.
It is selective law enforcement plain and simple.