UPDATED with Biden and Trump - Who were the best and worst U.S. presidents? In the past when historians and scholars have rated the presidents, their evaluations often have been based on individual charisma, activism, and service during periods of crisis.

Taking a distinctly new approach in Recarving Rushmore, Ivan Eland profiles each U.S. president from Washington to Obama on the merits of his policies and whether those strategies contributed to peace, prosperity, and liberty. This ranking system is based on how effective each president was in fulfilling his oath to uphold the Constitution. Contrary to the preferences of modern conservatives and liberals, this oath was intended to limit the role of the federal government.

Readers will be intrigued to discover why, of the four men given exalted representations on Mount Rushmore, only Washington deserves the honor. They will learn why Teddy Roosevelt has been overrated; why Jefferson hypocritically violated his lofty rhetoric of liberty; and why Lincoln provoked a civil war that achieved far less than believed. Readers will uncover why some presidents are rated much higher than the conventional wisdom—for example, Warren Harding—and some rank much lower—for example, Harry Truman.

As for more modern U.S. chief executives, Republicans will be astounded to learn that Nixon was the last liberal president and that Reagan wasn’t all that conservative. Democrats will be amazed to learn that Clinton was in some respects more conservative than George W. Bush and why both Obama and Bush are ranked as bad. Readers will learn why the author goes against the grain and anoints Eisenhower and Carter as the two best modern presidents.