From Texas Watchdog. If you're not familiar with why Miller's signing on to this bill might have the appearance of retaliation, read up on the Ronnie Earle indictments re: TAB and TRMPAC (tags below)

The state representative’s measure would again preclude the Travis DA from trying two of the most vital types of public corruption charges. Had the bill been in effect in 2005, Earle might not have been able to investigate DeLay at all.

I might mention that Miller's involvement in TRMPAC predates the indictment to ask to testfiy about the money-laundering trial.