Who is the supporter of value-laden approach of political theory ?

Leo Strauss was a foremost twentieth-century proponent of a value-laden, normative approach to political philosophy. He argued that political phenomena cannot be understood without making moral evaluations about the good society and strongly criticized the positivist and behaviouralist attempt to construct a 'value-free' political science (as advocated by thinkers such as George Catlin and Robert Dahl).