The unusual breakdown of Congress played a critical role in the early stages of the Cold War. With a shaky base of congressional support, Truman had little choice but to work with internationalist Republicans: more than flattery was at stake in Dean Acheson's attempts to woo Vandenberg and his ideological comrades, Henry Cabot Lodge II and H. Alexander Smith. The temperaments, ideologies, and inclinations of the internationalist Republicans made them players on virtually every foreign policy issue of the day. Their performance set the stage for a new way for Congress to exert influence: with the foreign policy powers of the federal government expanding at an exponential rate, members of Congress could maneuver through the resulting chaos.
From a completely different ideological perspective, other domestic forces also encouraged a congressional presence in the early Cold War. Following the elections of 1946, when Republicans captured control of both houses of Congress, more than half of the House GOP caucus petitioned for membership in the House Un-American Activities Committee (HUAC). One of these freshmen, California congressman Richard Nixon, made a national name for himself with his activities on the committee, especially after he exposed perjury by the former State Department official Alger Hiss. With the committee championing the anticommunist cause in the House, Republican Joseph McCarthy took up the banner in the Senate. The Wisconsin senator was the rare member of Congress who could shape the national psyche, and both the Truman and Eisenhower administrations had to deal with the consequences of his actions. In the process, while the liberal internationalist and Asia-first alternatives that Congress considered during the early portions of Truman's years fell by the wayside, the nationalists in Congress flourished.
Even during the height of his power, McCarthy sponsored no important laws; he sought to affect the national debate on anticommunism but eschewed the hard work necessary to pass legislation. Measured by that standard, the most influential member of the postwar Congress was Nevada senator Pat McCarran, who was responsible for two critical pieces of Cold War legislation: the McCarran Internal Security Act (1950) and the McCarran-Walter Immigration Act (1952). McCarran's position as a Democrat willing to buck his party's leadership and his considerable contacts with the Federal Bureau of Investigation gave him clout on Capitol Hill. In addition, the ability of figures like McCarran to work around the traditional congressional structure to have an impact—the senator's power base was the Judiciary Committee—provided a model for future congressional initiatives that challenged executive control.
In the years following Truman's decision to commit forces to the Korean conflict, Congress's role in warmaking notably declined, while the growth of executive agreements produced a similar diminution of the Senate's treaty-making power. These developments did not escape congressional notice. During the Truman administration, a group of nationalists led by Ohio's two GOP senators, John Bricker and Robert Taft, embraced the cause of congressional power. The duo argued that Truman-style internationalism would not be possible if Congress took its appropriate place as a partner of the executive on foreign policy matters.
With the election of Republican Dwight D. Eisenhower in 1952, liberal Democrats searched for a way to use congressional power to criticize the president without being labeled soft on communism. They urged a formal, symbolic role in framing policy, with the executive conceding the principle of legislative input in exchange for Congress allowing the president freedom of action to prosecute the Cold War. Hubert Humphrey (a member of the populist Democratic-Farmer-Labor Party of Minnesota) candidly described this stance as a "limited dissent." Indeed, as practiced in the Eisenhower administration, it actually came to less than that: Eisenhower pioneered the tactic—later made famous with the Tonkin Gulf Resolution—of submitting blank-check resolutions authorizing vaguely defined overseas actions. The relationship between Eisenhower and congressional Democrats suggested that genuine collaboration interested neither side.
But in many ways, a focus on the balance of power between Congress and the president misses the most important element in the legislative response to the early Cold War. That instead came in an internal congressional development: the creation of the culture of a Cold War Congress. The position of the Senate Foreign Relations Committee weakened as the international issues (warmaking and approving treaties) over which it had clear jurisdiction fell into disuse. Within Congress, the committee came under challenge from the newly created Joint Committee on Atomic Energy and the Senate Armed Services Committee, which both proved less than zealous in challenging executive policies. With the expansion of the defense budget, influence especially shifted to the Armed Services Committee, which viewed itself less as an oversight body than as a defender of the Pentagon and as a gatherer of defense contracts for members' congressional districts. Other aspects of the national security state, especially the intelligence community, similarly stood beyond congressional control.