Phrase often used to belittle others while smugly asserting superior morality, gained popularity during Clinton impeachment trial by Republicans.
Most often used by outraged Republicans against Democrats as in implying "I would never do that!" or "how could you!"
It's standard meaning is "Hypocrisy"
Senator Ensign (R) Governor Sanford (R) Both lectured President Clinton on "moral values" they felt having a girlfriend was sending a terrible message to the world. Called on him to resign for his shameful behavior.
They were so shocked they needed to know all the details!! What they did with all that scandalous information...well you know.