use a sledgehammer to crack a nut

The analogy dates back to at least the middle of the 19th century: see, for example, this quotation from Levi Carroll Judson’s work Sages and Heroes of the American Revolution (1851): “He at once became the nucleus around which a band of patriots gathered and formed a nut too hard to be cracked by the sledgehammer of monarchy.”

• "This last mentioned consideration involves the concept in Community law (derived principally from German law) called "proportionality". In plain English it means "You must not use a steam hammer to crack a nut, if a nutcracker would do.""
• "Today, Mr [Anthony] Worthington, an engineer, said: 'Sending three officers over simply to give a warning about kids playing football in the street is like using a sledgehammer to crack a nut.[…]'"
• "In our view the Public Order Bill is an attempt by the Government to use a sledgehammer to crack a nut. At a time when we should be focusing on rebuilding trust in the police, this Bill risks stoking further mistrust and undermining their vital role in protecting the public."

• use a sledgehammer to kill a gnat

• shoot an elephant with a BB gun
• kill an elephant with a BB gun

• break a butterfly upon the wheel
• bring a knife to a gunfight
• overkill
• when all you have is a hammer, everything looks like a nail