In meeting the challenges of his time, Kennedy sharply expanded the power of the presidency, particularly in foreign affairs. The 50th anniversary of his inauguration highlights the consequences—for him, for his successors and for the American people.
Truman would learn a paradoxical, and in his case bitter, corollary: with greater power, the president also had a greater need to win popular backing for his policies. After the Korean War had become a stalemate, a majority of Americans described their country’s participation in the conflict as a mistake—and Truman’s approval ratings fell into the twenties.
After Truman’s experience, Eisenhower understood that Americans still looked to the White House for answers to foreign threats—as long as those answers did not exceed certain limits in blood and treasure. By ending the fighting in Korea and holding Communist expansion to a minimum without another limited war, Eisenhower won re-election in 1956 and maintained public backing for his control of foreign affairs.
Then it moves on to Kennedy:
Unlike Truman, Kennedy was already quite aware that the success of any major policy initiative depended on a national consensus. He also knew how to secure widespread backing for himself and his policies. His four prime-time campaign debates against Nixon had heralded the rise of television as a force in politics; as president, Kennedy held live televised press conferences, which the historian Arthur Schlesinger Jr., who was a special assistant in the Kennedy White House, would recall as “a superb show, always gay, often exciting, relished by the reporters and by the television audience.” Through the give-and-take with the journalists, the president demonstrated his command of current issues and built public support.
The article ends with Obama's position coming on the end of this progression:
Barack Obama does not appear to have fully grasped the Truman lesson on the political risks of unilateral executive action in foreign affairs. His decision in late 2009 to expand the war in Afghanistan—albeit with withdrawal timelines—rekindled worries about an imperial presidency. Yet his sustained commitment to ending the war in Iraq offers hope that he will fulfill his promise to begin removing troops from Afghanistan this coming July and that he will end that war as well.
Perhaps the lesson to be taken from the presidents since Kennedy is one Arthur Schlesinger suggested almost 40 years ago, writing about Nixon: “The effective means of controlling the presidency lay less in law than in politics. For the American President ruled by influence; and the withdrawal of consent, by Congress, by the press, by public opinion, could bring any President down.” Schlesinger also quoted Theodore Roosevelt, who, as the first modern practitioner of expanded presidential power, was mindful of the dangers it posed for the country’s democratic traditions: “I think it [the presidency] should be a very powerful office,” TR said, “and I think the president should be a very strong man who uses without hesitation every power that the position yields; but because of this fact I believe that he should be closely watched by the people [and] held to a strict accountability by them.”