Answer:
The longest filibuster.
Explanation:
A filibuster is a political tactic where one or more members of the parliament discuss the matter of debate for a long time, to delay the final decision.
Senator Strom Thurmond holds the record, however, this tactic has been widely used in the past, as far as the roman empire. When the roman senator Cato the Younger was opposed to any legislation he would often delay the measures, by pronouncing a speech that lasted until nightfall.
As an interesting fact, despite senator Thurmond's fierce opposition, The Civil Rights Act of 1957 was still passed by the US Congress and was signed by President Dwight D. Eisenhower.
