"We have a constitutional system that so fragments and divides power that it's impossible to give this country effective, long-run leadership . . . . The system has led to an inability to plan and get on top of problems ahead of time. Even at best, this country has always been twenty to sixty years behind other industrial democracies in dealing with tough problems." -- James MacGregor Burns, 1988
Which aspect of United States government might Burns cite to support his argument?