The revolutionary era bequeathed an appropriately ambivalent record regarding the legislative role in foreign affairs. The new country's first government, the Articles of Confederation, granted all international authority in the Continental Congress. But this structure proved awkward, and on two occasions the Congress divested itself of the day-to-day conduct of diplomacy by appointing a secretary of state for foreign affairs. At the state level, too, executive power over militias rebounded to some degree as the revolutionary war proceeded. Finally, almost all who served as delegates to the Constitutional Convention agreed that the Articles regime could not permanently protect the weak state from national security threats.
The convening of the Constitutional Convention thus coincided with a period of intellectual ferment regarding the proper executive-legislative balance in foreign affairs. It came as little surprise that the resulting document gave neither branch clear-cut dominance on international matters, but it seemed as if Congress would have the predominant voice in the new government's foreign policy. For instance, quite beyond the power to declare war, the legislature received the commercial powers (important given the framers' belief that economic affairs would dominate post-revolutionary international relations) and the ability to issue letters of marque (the eighteenth-century equivalent of a right to wage undeclared war). Yet legal scholarship has never developed a consensus on the precise extent of Congress's warmaking power, partly because the Constitutional Convention's Committee on Style changed the Constitution's wording from giving Congress the power to "make war" to the power to "declare war."
Beyond the warmaking issue, the question of constitutional intent grows even murkier. Several framers, notably Gouverneur Morris and James Madison, described the appropriations power as the ultimate guarantee of congressional predominance in foreign affairs. But the experience of the treaty-making clause (where, at the last minute, the framers involved the executive in the process after initially planning to grant all treaty-making power to the Senate) suggests that the intended balance between the two branches changed in the president's favor as the Constitutional Convention proceeded. Memories of the chaotic and indecisive foreign policy of the Confederation period may very well have caused the framers to reconsider congressional dominance in international affairs.
The diplomacy of the early Republic, however, featured a much weaker legislative role than even the most ardent advocates of executive authority could have anticipated. In a variety of initiatives, George Washington asserted executive primacy. His handling of the nation's first treaties—with the Indian nations and then Jay's Treaty with England (1795–1796)—decreased the Senate's advisory capacity. His proclamation of neutrality in the wars of the French Revolution and his response to the revolt in Haiti strengthened the executive's hand in interpreting treaties already on the books. When Congress investigated Arthur St. Clair's disastrous military defeat by Indians on the Ohio frontier in November 1791, Washington established a precedent by invoking executive privilege so that he could withhold documents from Congress.
Although rhetorically committed to a strong foreign policy role for Congress, Thomas Jefferson also articulated a domestic agenda that aimed to forestall the corrupting effects of industrialization through territorial expansion and overseas commerce. When forced to choose between strict constructionism and his ideals, he consistently selected the latter. The most spectacular case was the Louisiana Purchase, but the most constitutionally significant came in the wars against the Barbary states—North African states whose piracy threatened Jefferson's vision of the United States carrying on an active worldwide commerce in agricultural goods. The president undertook a naval campaign without a direct declaration of war, and his policy would be cited for generations to come to justify unilateral presidential warmaking. In addition, Jefferson's effective leadership of the Republican legislative majorities allowed him to bypass a rather supine Congress on foreign policy matters. Even James Madison, who justifiably lacks a reputation as a strong president, successfully expanded executive authority. Most scholarship now downplays the significance of congressional "warhawks" such as Henry Clay and John Calhoun in forcing the president's hand to enter the War of 1812. Moreover, beyond European affairs, Madison retained primacy over policy toward the revolts in Spanish America. He consistently opposed extending diplomatic recognition to the rebellious colonies, which, because the Senate had power to confirm all ambassadors, would have involved the legislature in Latin American policy. Instead, Madison relied on private agents, unauthorized by Congress, and thus expanded executive power even further.
In contrast to such executive assertiveness, congressional attempts to establish a foothold in international affairs floundered. As Washington demonstrated, the treaty-making power did not guarantee a clear role for the Senate in making foreign policy. At the same time, the failure of House Republicans to block appropriations to implement Jay's Treaty provided the first in a series of unsuccessful attempts by the lower chamber to increase its international role. That this setback established a precedent, however, would only gradually emerge; over the next quarter century, factions within the House repeatedly challenged the constitutionality of executive predominance in foreign policy. But such initiatives, emanating from arch-Jeffersonian forces around Albert Gallatin in the 1790s, the Federalists in the early 1800s, and the small band of "Old Republicans" led by John Randolph in the 1810s, all fell well short of majority support.