Do you agree with the authors' thesis that the Progressive Era marks a fundamental shift in American political thought? How would you evaluate this quote: "Whether one regards the transformation of American politics over the past century as good or bad, the foundations of that transformation were laid in the Progressive Era. Today's liberals, or the teachers of today's liberals, learned to reject the principles of the founding from their teachers, the Progressives." What are the principles he is referencing? Is he correct in characterizing 20th-century progressives as being more aligned with the founding principles they pushed back against than with today's liberals? If so, how do you account for this shift? If not, how would you characterize them?