If you keep to the letter of the law, you act according to what is actually written in the law, the exact words, rather than the intent of those who wrote the law.
"To comply with the letter of the law, he was fined for allowing his son to take his toy tractor to the park. The sign said: “No vehicles permitted.”! "
An officially authorized activity which enables people to make a lot of money without much effort is called a licence to print money.
"The contract to supply computers to schools was a licence to print money."
This expression refers to the extensive power of the authorities or the police.
"The suspect got away but he won't escape the long arm of the law for long."
Murphy's law
Referring to Murphy's law expresses a sentiment of bad luck and the idea that if anything can go wrong, it will.
"We've tried to prepare for every possible incident, but remember Murphy's law ...!"
To say that someone doesn't have a leg to stand on means that they can't prove what they say or do not have valid arguments to support their position.
"Three people testified against him. He didn't have a leg to stand on."
Something which isnull and void has no legal force or is invalid.
"The contract was declared null and void."
open-and-shut case
An open-and-shut case is one where the facts are so clear that the matter can be dealt with or solved easily.
"He was caught driving the stolen car. It's an open-and-shut case."
paper trail
If a person or organisation leaves a paper trail, they leave evidence in writing or in document form that will serve as proof of their actions.
"The police found a paper trail which lead to the author of the hoax."
