Seventy years ago this month, Harry S. Truman was thrust into the presidency upon the death of Franklin D. Roosevelt.

Did a hand-wringing press make excuses for the newly minted vice president when FDR's untimely death foisted presidential duties upon him after less than three months?  In the midst of World War II, Mr. Truman did indeed have big shoes to fill and the grave responsibility to continue the fight against the tyrannical Axis powers of Hitler, Mussolini, and the Japanese, who threatened to plunge the globe into perpetual totalitarian darkness.  Did he petulantly stamp his foot, grouse, and curse the heavens for his fate?  No – Mr. Truman, a farm boy in his youth, put the plow to work a politically scorched earth.  His motto: "The Buck Stops Here," a desk sign displayed proudly in the Oval Office.  With victory seriously in doubt and millions of lives hanging in precarious balance, were these circumstances to Mr. Truman any less daunting than what Mr. Obama faces today?  What good would it have done Mr. Truman, or anyone else for that matter, to blame the previous guy to sit in the big chair?

That is the point: the U.S. presidency is a big-boy or future big-girl job.  Anyone who doubts that leading a nation – and the free world – is tough should look at before and after photos of the men who have resided in the White House.  Despite fast planes, bulletproof limousines, a lectern on the world stage, and the ultimately superficial comforts of five-star accommodations, the job is a pressure-cooker.  As Enlightenment writer Voltaire said, “With great power comes great responsibility.”  Current U.S. leaders of every stripe should take a lesson.