* This is, almost without a doubt, the most important ruling that Judge Zagel will make in Bill Cellini’s upcoming trial…

Federal prosecutors on Tuesday asked a judge in an upcoming corruption trial to block “irrelevant” questions about the personal life of the expected star witness: serial swindler Stuart Levine.

Prosecutors say defense lawyers for Springfield power broker William Cellini, a onetime co-defendant of former Gov. Rod Blagojevich, should not be allowed to delve into Levine’s lurid background, including Levine’s previous testimony that he’d engage in all-night, drug-fueled parties at the Purple Hotel in Lincolnwood and then attend a meeting for a state board the following day. […]

By limiting Levine’s cross examination, the government is trying to avoid the same 15-day saga that played out in Tony Rezko’s 2008 corruption trial, where Levine, once a GOP supporter and the member of two influential state boards, spelled out many details of his personal life, arguably creating a distraction in the trial.

“The government anticipates that the defendant will attempt to introduce evidence or cross-examine Stuart Levine, a potential government witness, on certain matters that are irrelevant and/or unduly prejudicial, such as on matters pertaining to Levine’s drug use and personal life,” prosecutors wrote in Tuesday’s filing. Some of those papers were filed in private with the judge at the government’s request.

Tony Rezko’s attorneys were able to bring up much (but not all) of Levine’s past, which included seemingly constant cocaine use and drug-filled parties with young men in the Chicago area and, on at least one occasion, Springfield.

Rezko’s defense was, essentially, that Levine had made the whole thing up. There was no attempt to shake down investor Thomas Rosenberg for a $1.5 million campaign contribution because the plan never existed, except in Levine’s drug-addled mind. The jury agreed. Rezko was acquitted of these Levine-related charges.

Judge Zagel disallowed this particular line of questioning in the Blagojevich trial, but Levine was never called to the stand. The alleged shakedown attempt wasn’t part of that trial.

* If the proseuction wins on this point, Levine’s testimony will be almost golden. If Cellini’s lawyers win the round, then Levine will once again be forced to reveal his lurid past and the prosecution will be at a distinct disadvantage. Keep in mind that the prosecution’s entire case against Cellini is built on this alleged shakedown attempt and that Rosenburg has already testified that Cellini never asked him for a dime. If the shakedown scheme is seriously undermined once again, then Cellini may have a decent chance at winning here.

The rest of the Cellini legend will be a factor, of course, but the centrality of the case is this alleged shakedown, which was already found once to be a fantasy.

* Read the prosecution’s filing by clicking here.