In an interview in the summer of 1965, McGeorge Bundy, a former Harvard dean who served John F. Kennedy and Lyndon B. Johnson as national security adviser and was an architect of the Americanization of the Vietnam War then underway, was asked what was different in the actual conduct of American diplomatic affairs from how it had seemed to be “from the safety of Harvard Yard.” Bundy replied that the first thing that stood out was “the powerful place of domestic politics in the formulation of foreign policies.”

It was a revealing comment, but not one that should surprise us (except to the extent officials seldom make this admission on the record). For the relationship between domestic politics and foreign policy has been an intimate one throughout the nation's history. It may be debated whether the connection is a good thing or a bad thing – whether overall it has been beneficial to the nation's record on the world stage – but for the moment it is enough to say that it is there and is important. The key shapers of US foreign policy have been politicians, who understand that developments far from America's shores can deeply influence their prospects at the polls, their careers, and their reputations. So it has been with presidents, the most important makers of foreign policy. So also with secretaries of state and defense, who, though often nonpoliticians, are bound to the president's political positions. So with many of those who have headed diplomatic missions abroad; now, as from the republic's early days, many of these assignments are handled under political patronage. So also with lawmakers on Capitol Hill who devote their energies to world affairs and with other leaders in both major parties, in and out of office.

Being officeholders or career-minded appointees, these individuals could hardly be expected to forget domestic politics when they are weighing foreign policy alternatives. And as a general rule in US history, they have not. Already in 1796, it is well to remember, George Washington publicized his Farewell Address partly in order to assist his vice president, John Adams, in the presidential election against Thomas Jefferson – the Address, justly celebrated by later historians as a powerful articulation of foreign policy principles, also served a nakedly partisan purpose.