The power of the US presidency has expanded considerably over 235 years. But has it gone too far and broken our system of separation of powers? If so, how do we (and especially the US Supreme Court) rein it back in? Retired attorney Peter Cohen looks at these questions in his new book, "In the Supreme Court's Own Words: First Principles for Checking Presidential Power and Preserving the Republic." Our conversation includes discussion about how to make legal rulings more understandable, constitutional restraints that presidents of both parties have tested, whether the "activist judge" argument has caused problems in our political discourse, and how we change our opinion on expanded presidential power based on whether we support the president.