To use excessive force to accomplish something that can be done with far less.
Break a butterfly on a wheel: Sending a SWAT team to deal with a fifteen year old kid disturbing the peace by having his music turned up too loud.
The original phrase "Who breaks a butterfly upon a wheel?" was a line from the poem "Epistle to Dr Arbuthnot”, which referenced an ancient torture method known as the “breaking wheel” or “Catherine wheel”.