Kennedy took a page from Eisenhower's book and then added chapters of his own. Having learned the crucial lesson that popular support was key to presidential power, Kennedy exploited the important new medium of TV to communicate directly and eloquently with the American citizenry. Deploying his considerable charm and wit, Kennedy was able to maintain his popularity even in the face of an early setback like the 1961 Bay of Pigs fiasco. When the U.S.-backed "invasion" of Cuba was annihilated by Fidel Castro's troops, Kennedy went before the cameras to candidly assume full responsibility for the disaster. The public forgave him, and his popularity ratings actually rose. His successor, Lyndon Johnson, failed to learn the lesson and acted without Congressional or popular support in Vietnam, ending up politically ruined.
Since then, presidential power has waxed and waned with a given leader's ability to gather and maintain public support. This ability has rested on the president's communication skills. Presidents possessed of the rhetorical talent necessary to connect with the public have fared better than those more prone to operate on the down-low.
The 1970s Watergate scandal was a major blow to executive authority because it revealed just how much Richard Nixon was hiding from the electorate. Clandestine operations gone wrong during the Carter and Reagan administrations further eroded executive authority to such an extent that when George H.W. Bush decided to go to war with Saddam Hussein in 1991, he asked Congress for a resolution first.
In subsequent years, presidents have done a bit of both, getting congressional support where necessary and conducting unilateral operations where expedient and unlikely to damage popularity ratings. Barack Obama's use of drone strikes is a clear example of a president conducting military actions abroad without risking the blood and treasure that sank George W. Bush's numbers so low in the wake of the Iraq and Afghanistan invasions. While George W. had supportive resolutions from Congress for these actions, he didn't have proper declarations of war, which might have helped spread the blame for those unpopular conflicts more evenly and saved him from the catastrophic drop in his popularity.
When a president's popularity wanes, he often feels the pain in the form of a midterm election that lands him with a hostile Congress, which can veto his veto and/or simply refuse to work with him. In such cases, a president usually turns to the consolation of executive orders. And when a president starts seriously wielding his executive orders in order to bypass Congress, he's almost always accused of being an "imperial president." This is a charge Republican members of Congress have repeatedly levelled at Barack Obama.
A glance at the archives shows that while Obama has made liberal use of executive orders to further his political agenda, he's got nothing on his predecessors. He has issued fewer than 300 orders, while predecessors like Ronald Reagan (381), Dwight Eisenhower (484), Harry Truman (907) and Woodrow Wilson (1,803) far outstrip him. Topping the list is Mr. Executive Order himself, Franklin Delano Roosevelt, with a jaw-dropping 3,721 [source: American Presidency Project].