The phrase elastic clause comes from the Necessary and Proper Clause - the article I section 8 of the Constitution and it lists the Congress powers. The problem faced by the framers of the Constitution was that it was impossible to list every single power of the government, they wanted to make the article relevant to the changes of the world. This is the reason it is called the elastic clause, because at the the end of Section 8 it says “Congress has the power to make all laws which shall be necessary and proper for carrying into execution the foregoing powers and all other powers vested by this constitution in the government of the united states or any department or office thereof”.
