Odd though it may seem, ideological conservatives used to be fierce critics of "executive supremacy."
For instance, in 1940, when Franklin D. Roosevelt sought a precedent-breaking third term, the archconservative Herbert Hoover warned that Roosevelt was a virtual dictator whose growing "personal power over the last seven years" came at the expense of a "disastrous weakening of the legislative and judicial branches" with Congress "reduced to a rubber stamp for the executive."
As the Cold War raged, conservatives opposed to the centrist policies of President Dwight D. Eisenhower backed a constitutional amendment granting Congress the authority to curtail presidential treaty-making powers. It came within a single vote of passage in the Senate in 1954.
The battle was also fought on the intellectual front. In his book Congress and the American Tradition, the conservative thinker James Burnham argued that the founders had envisioned a government in which "the preponderating share of power was held and exercised by the legislature," primarily the House, since its members were directly accountable to their local constituents, unlike presidents, who wielded power through Caesarist manipulations of "the mob."
It all looked very different to liberals. The historians Richard Neustadt and Arthur Schlesinger Jr., both advisers to President John F. Kennedy, urged him to mimic Roosevelt's activist approach, while a third historian, James MacGregor Burns, declared in his book Presidential Government that "the stronger we make the president, the more we strengthen democratic procedures and can hope to realize modern liberal democratic goals."
But when an uncongenial president, Lyndon B. Johnson, took the Roosevelt model even further, some liberals began to question the virtue of the strong executive. "The president of the United States has become an uncrowned king," the political scientist Hans Morgenthau wrote in 1966. "Lyndon B. Johnson has become the Julius Caesar of the American Republic."
Schlesinger, too, began to rethink. "It is evident now that this delight in a strong presidency," he noted in his journal in 1967, "was based on the fact that, up to now, all strong presidents in American history have pursued policies of which one has approved." In his book The Imperial Presidency, Schlesinger acknowledged that the executive overreach that led to Vietnam and Watergate owed something to the excesses of the Kennedy administration. Meanwhile, conservatives emerged as the new champions of executive supremacy. It was they who defended Richard M. Nixon during Watergate and then Ronald Reagan during the Iran-Contra scandal. And today some support the "presidential prerogatives" of George W. Bush.
Left and right, it appears, have conveniently adjusted their arguments — depending, in most cases, on who happens to be in the White House.