The Federalists’ strong opposition to the expansion of slavery was multifaceted. It was partly political. The three-fifths clause of the Constitution had granted slave-owning states such as Virginia a numerical advantage in Congress and the Electoral College. The Federalists, concentrated in northern states, had seen this numbers game play to their disadvantage when Jefferson, a Virginian, bested the sitting president John Adams, from Massachusetts, in the election of 1800. The addition of more slave-holding states from the newly acquired Louisiana Territory threatened to deepen the Federalists’ electoral distress.

But the Louisiana dissenters also offered a moral argument against the expansion of U.S. territory and thus the spread of what Senator Hillhouse called “a serious evil.” Hillhouse also worried that the expansion of slavery into Louisiana would threaten national security. Because “these slaves [were] men [with the] the passions and feelings of men,” the danger of slave rebellion was ever present. Louisiana dissenters recounted horrific tales from white refugees of the slave rebellion in Saint-Domingue (modern-day Haiti) to buttress this point. The need to extinguish this danger would necessitate a standing army to keep the peace, an idea that was anathema to the Federalists—and another clear violation of the Constitution.

Such arguments failed to persuade most Americans. The right of slave-owners to carry into the new territories what the law recognized as property was never seriously in question. Slave-owners alleged that only Africans could safely cultivate the land, whereas whites would struggle to survive in the oppressive heat and humidity of the Deep South. Ensuring the most efficient use of this vast land, of importance to both the northern and southern economies, thus depended—so the argument went—upon slavery. The brief but heated debate over Louisiana presaged later arguments about slavery that would eventually tear the nation apart. They next played out in the debate over another major territorial expansion: the admission of Texas to the Union and the accession of former Mexican lands.

 War with Mexico

“The United States,” notes historian George Herring, “had long coveted Texas,” and in the 1840s other Mexican territories, including California and modern-day New Mexico, “also became objects of desire.”

The rationales in favor of acquiring these lands echoed those from the brief debate over Louisiana—especially the idea that American security and prosperity both depended on territorial expansion. But the presence of over 30,000 former U.S. citizens who had accepted the Mexican government’s offer of cheap cotton-growing land added a distinctive flavor to the Texas debate.

These men had uprooted their families—and their slaves—and moved west, but they soon grew tired of what they perceived to be an overly intrusive Mexican government meddling in their business affairs. Concern that Mexico might ban the use of slave labor only heightened the recent arrivals’ anxiety. When they declared Texas an independent state in 1836, the Mexican government attempted to put down the revolt. It instead got a war with the United States that would ultimately result in a humiliating defeat and the loss of 40 percent of its territory.

The Texas rebels had successfully drawn the U.S. government to their side. In truth, it didn’t take that much effort; President James K. Polk, an avowed expansionist, was only too happy for the opportunity.

But not all Americans were as enthused as Polk about Texas’s accession to the Union, specifically, or territorial expansion generally.

Some questioned the wisdom or even the need to expand for the purposes of defending the United States from foreign threats. The likelihood of such threats materializing, they said, was vanishingly small. According to a 28-year-old Abraham Lincoln in a speech in his hometown of Springfield, Illinois, the greater danger came from within:

At what point shall we expect the approach of danger? By what means shall we fortify against it? Shall we expect some transatlantic military giant, to step the Ocean, and crush us at a blow? Never! All the armies of Europe, Asia and Africa combined, with all the treasure of the earth (our own excepted) in their military chest; with a Buonaparte for a commander, could not by force, take a drink from the Ohio, or make a track on the Blue Ridge, in a trial of a thousand years.

At what point then is the approach of danger to be expected? I answer, if it ever reach us, it must spring up amongst us. It cannot come from abroad. If destruction be our lot, we must ourselves be its author and finisher. As a nation of freemen, we must live through all time, or die by suicide.

Others voiced similar concerns. Daniel Webster fretted over the “dangerous tendency and doubtful consequences to enlarge the boundaries of this country, or the territories over which our laws are now established.” “If we would make our institutions permanent,” Webster continued, “there must be some limit to the extent of our territory.”

Several years later, Webster opposed the Mexican War on the same grounds: expanding the United States far beyond its current borders would weaken the institutions of government. He said:

We want no extension of territory, we want no accession of new States. The country is already large enough. I do not speak of any cession which may be made in the establishment of boundaries, or of the acquisition of a port or two on the Pacific, for the benefit of navigation and commerce. But I speak of large territories, obtained by conquest, to form States to be annexed to the Union; and I say I am opposed to such acquisition altogether.

Webster and other northerners correctly worried that the new states acquired from the Mexican War would likely be slave states, upsetting the delicate balance of power in Congress that had been established in the Missouri Compromise of 1820. But they also complained of how the Mexican War had provided an opening for President Polk to circumvent some of the most cherished principles of the Constitution, including especially Congress’s control over the war power.

In 1846, Polk had sent American troops into territory claimed jointly by Mexico and the United States. When Mexican forces attacked U.S. General Zachary Taylor’s contingent, Congress declared war. Polk had effectively circumvented Congress in order to precipitate a conflict. Two years later, Congress formally censured Polk for exceeding his authority, but by then the damage had already been done: Polk’s actions had disturbed the peace and upset the balance between the executive and Congress.

Polk’s actions caught the attention—and ire—of a young lawmaker from Illinois. “Allow the President to invade a neighboring nation, whenever he shall deem it necessary to repel an invasion,” wrote Abraham Lincoln in a letter to his law partner, “and you allow him to do so, whenever he may choose to say he deems it necessary for such purposes—and you allow him to make war at pleasure.” He went on:

The provision of the Constitution giving the war making power to Congress, was dictated, as I understand it, by the following reasons. Kings had always been involving and impoverishing their people in wars, pretending generally, if not always, that the good of the people was the object. This, our convention understood to be the most oppressive of all kingly oppressions; and they resolved to so frame the Constitution that no one man should hold the power of bringing this oppression upon us.

Lincoln understood this history, but Polk understood power. He wouldn’t be the last president to exceed his authority in the quest to expand the boundaries of the United States. He also wouldn’t be the last president forced to contend with the opponents of such expansion. The most consequential period of territorial expansion concerned the acquisition of faraway lands, chiefly islands separated by hundreds or many thousands of miles of water from the American people and the American government. The next chapter focuses on the spirited debate occasioned by the United States’ brief war with Spain and especially by its handling of Spain’s former colony, the Philippines.

Christopher Preble is vice president for defense and foreign policy studies at the Cato Institute and the author of Peace, War, and Liberty: Understanding U.S. Foreign Policy.

Image: Reuters