Chris Satullo, talking sense as usual on the Inquirer editorial page:
Our political discourse has a bad case of the "butwhatabouts."It's a reflex of partisanship, a way to muffle news that looks bad for your team.
Here's how it works: When embarrassing news breaks, swiftly begin harping on an earlier, superficially similar incident that involved bad behavior by the other team.
The goal is not to illuminate or place in context, but to obscure and evade.
To this end, insist (with scant regard to the facts) that the earlier sin was much, much worse, but was treated much more leniently - by the courts, or the biased jackals of the media, or both.