In defense...if it's okay.
Please remember----what he failed to report was not income per se. It's not as though someone was giving him money for supplies or services "under the table".
No one on this forum has ever done anything like that, have they? You would never say; "Cash is king" and peel off a few bills expecting a discount, would you?
This senator (former, by the way---he was not in office during the period in question) received the loan of a vehicle and driver on a periodic basis from a fellow he had known for a long time and with whom he had recently gone into business.
His error was in failing to convert the value of that "gift" into money and then declare that amount in his taxation year.
Apparently, the IRS requires that calculation.
Anybody else ever mistakenly fail to declare all income from all sources---or perhaps, inadvertently "over-state" or mis-characterize an expense.
Let he who is without sin...etc.