- Withdrawing his own money from his own bank accounts in unapproved amounts; and
- Lying to the FBI about why.
In anything resembling a free -- or even sane -- society, neither of those things would be crimes.
Rachel Maddow used the word "forever" last night to describe federal laws 1) requiring banks to report transactions in excess of $X and 2) making it illegal to conduct transactions of less than $X to avoid the reporting requirements. My recollection is that she has it completely wrong; such laws first went into place in the mid-to-late 1990s (e.g. "Know Your Customer") and got tweaked in the early 2000s (the "USA PATRIOT Act"). That, by the way, would have all been on Denny Hastert's watch.
In a free -- or even sane -- society, what you did with your money would be your business and nobody else's. Ditto lying about it to busybodies to/with whom you had no contractual obligation to speak truthfully or non-aggression obligation to not defraud.
The implication in the indictment is that Hastert was being blackmailed; that he was paying "hush money" to and an unidentified "Individual A" in order to keep that someone from going public with some kind of damaging information.
If that damaging information pertains only to Hastert and to the person being paid off -- that is, if what was being covered up was not itself aggression against/involving some third party -- I also don't see why anyone but Hastert and "Individual A" should have any say in the matter (see Walter Block on blackmail for why).
But if the state does have such an interest, it seems to me that according to the state's own disclosures, Hastert was the victim, not the perpetrator of blackmail/extortion. So why is it that he's been indicted, but "Individual A" has not?