Federal investigators should spare no effort in learning just how widespread the conspiracy allegedly involving Illinois Gov. Rod Blagojevich has been.
Blagojevich and his chief of staff were arrested last week, charged with misbehavior involving political corruption.
Perhaps the most shocking allegation is that Blagojevich, who must name a U.S. Senate replacement for President-elect Barack Obama, attempted to sell the office to the highest bidder.
Investigators have the governor on tape, through court-ordered wiretaps. The tapes allegedly reveal that Blagojevich wanted personal benefits for himself and his wife, in exchange for an appointment to the Senate.
The question now is how far the corruption spread. To judge by other, unrelated accusations against Blagojevich, people other than himself and his chief of staff have been involved in various schemes.
Investigators should unmask everyone in government who is involved in the corruption - whether it relates to this week's charges or others during the past few years. In addition, more needs to be known about those who may have been willing to offer bribes. They should not be allowed to walk away unscathed just because their schemes did not bear fruit.
Blagojevich is innocent until proven guilty, of course. But investigators' tapes are powerful evidence of wrongdoing. More needs to be known about how far the corruption spread - and who was involved in it.