Call it "pay for play" or "quid pro quo" - it only matters in the context to which the concept is applied.

That's the opinion of the judge in former Illinois Governor Rod Blagojevich's retrial on charges he offered preferrments in exchange for campaign cash.

The Chicago Tribune:

Sometimes even the little things can be telling in a criminal trial, and so it was this past week when U.S. District Judge James Zagel delivered a brief discourse on the nuances of political deal-making to lawyers at the corruption retrial of former Gov. Rod Blagojevich.

All deals involve some kind of quid pro quo, explained Zagel, once a top official in the administration of Illinois Republican Gov. James R. Thompson. "But 'quid pro quo' has one meaning in bribery and another in a legislative sense," Zagel continued.

The mini-lecture, delivered at a hearing out of the earshot of jurors, framed a critical dilemma for Blagojevich's lawyers as they began to mount a defense that featured their client as the star witness.

A central premise of that defense is that Blagojevich was engaged in routine and aboveboard deal-making that the government is trying to portray as criminal, in particular the way he went about flexing his authority to fill the U.S. Senate seat vacated by Barack Obama after the 2008 presidential election.

Prosecutors say Blagojevich tried to sell the seat; Blagojevich said he wanted to use it as a bargaining chip to extract legislative concessions from his political nemesis, Illinois House Speaker Michael Madigan. To that end, the defense asked permission to play for jurors a recording of a late 2008 phone conversation in which former U.S. House Speaker Dennis Hastert advised Blagojevich to obtain a "quid pro quo" from Madigan as part of any deal to hand the Senate post to the speaker's daughter, Lisa.

But Zagel disallowed that recording, suggesting that Blagojevich's lawyers were trying to use it to fuzz up the difference between the sort of "legitimate political deal" that Hastert was referring to and the unsavory variety of which Blagojevich stands accused.

Blago offered that seat to several politicians, including Jesse Jackson, Jr. who ended up holding a fundraiser for the governor. It's also clear from the tapes that the Obama transition team lied about the extent to which they were involved in horse trading for the seat.

But as the definition relates to Blago's trial, it seems clear that the judge has laid down a clear line between what was legal and illegal. If the jury can grasp this definition, it seems certain that Rod Blagojevich will be convicted of further counts in his corruption trial.