Allegedly Dennis Hastert was being blackmailed by a victim of his past.  Surfacing now are reports that while he was a teacher and coach in Illinois, prior to congress, he sexually molested a victim.  That victim blackmailed him.  The blackmail was exposed by the FBI/Treasury tracking large cash withdrawals from his bank account.
More thoughts after article:

YORKVILLE, Ill. — J. Dennis Hastert, the longest-serving Republican speaker in the history of the U.S. House, was indicted Thursday by a federal grand jury on charges that he violated banking laws in a bid to pay $3.5 million to an unnamed person to cover up “past misconduct.”
Hastert, 73, who has been a high-paid lobbyist in Washington since his 2007 retirement from Congress, schemed to mask more than $950,000 in withdrawals from various ac­counts in violation of federal banking laws that require the disclosure of large cash transactions, according to a seven-page indictment delivered by a grand jury in Chicago.

The indictment did not spell out the exact nature of the “prior misconduct” by Hastert, but it noted that before entering state and federal politics in 1981, Has­tert served for more than a decade as a teacher and wrestling coach at Yorkville High School in Illinois.
In 2010, confronted about the “prior misconduct,” the former speaker agreed to pay $3.5 million to the person “to compensate for and conceal his prior misconduct against Individual A,” prosecutors alleged.
That person, whose identity was shielded by prosecutors, has known Hastert most of his or her life, growing up in Yorkville, the city next to Hastert’s home town of Plano, in the exurbs west of Chicago. Prosecutors said the actions “occurred years earlier” than the 2010 meeting that sparked the payments.
In a statement Friday, the Yorkville school district that employed Hastert from 1965 to 1981 said it “was first made aware of any concerns” about him when he was indicted Thursday.
“Yorkville Community Unit School District #115 has no knowledge of Mr. Hastert’s alleged misconduct, nor has any individual contacted the District to report any such misconduct,” the statement said. “If requested to do so, the District plans to cooperate fully with the U.S. Attorney’s investigation into this matter.”  (read more)
Obviously I’m not defending the guy on the aspect that led to the bribery.  However, this Bank Treasury and Secrecies Act, that led to his arrest, is ridiculous.  I have felt that way for years. 
It was his money, nothing stolen, nothing fraudulent, nothing illegal about his financial accounts at all.  It was the way he was withdrawing the money that put him in trouble.  Financial transactions of $10,000 or more are required by law to be reported to the U.S. Treasury by the financial institution. 
If you withdraw, or deposit, amounts over $10k the U.S. Treasury is notified. 
Hastert was caught because he was making multiple cash withdrawals just below those limits in order to avoid the compliance reporting.  This is called “structured transactions”,  he then lied to the FBI about it when questioned. 
But remember, it’s his money to begin with.  What right does the government have to tell you how much, where and when you can withdraw your own assets?
If Hastert had just said: ‘yes, I’m withdrawing large amounts of cash in numerous transactions because I’m being blackmailed for something terrible I did in life’, and then continued withdrawing the money in amounts over the $10k, or in whatever amounts he needed, he wouldn’t be doing anything wrong – and the police/FBI would leave him alone. 
Alas, it was him trying to avoid the bank notifications, and then lying about them, that led to his arrest.