A '''fifth column''' is a group of people who rationally and clandestinely tries to undermine a larger group to which it is expected to be loyal. The expression dates from the [[Spanish Civil War]] in 1936 when the Francoist General Mola, whose forces were threatening Madrid, boasted that he had four columns approaching the city and a fifth column within it. | A '''fifth column''' is a group of people who rationally and clandestinely tries to undermine a larger group to which it is expected to be loyal. The expression dates from the [[Spanish Civil War]] in 1936 when the Francoist General Mola, whose forces were threatening Madrid, boasted that he had four columns approaching the city and a fifth column within it. |