A heckler is a person who shouts a disparaging comment at aperformance or event, or interrupting set-piece speeches, for example at a political meeting, with intent to disturb its performers or
participants.
Heckling appears to be the Republicants best hope for countering Obama's health care plan. They've used it in town hall meetings, even heckling chronically ill persons in wheelchairs trying to explain what they've endured, now they've done during a President's speech.
My initial reaction to the angry ejaculaton of YOU LIE! by House Rethuglican Joe Wilson, from the birthing place of the Confederacy and the Civil War - South Carolina, (also home to a philandering and mendacious Governor), was to attribute it to his crackerassed angry racist white man's contempt and derision for a powerful black man in a position of authority who was exercising it.