The German submarine Deutschland docked in Baltimore, Maryland, on July 9, 1916, after four weeks at sea. It was a merchant vessel carrying a cargo of medicine and dyes. Its arrival in the United States, still a neutral country, sent a message to the other warring European nations that Germany would be able to cross the Atlantic for supplies and repairs. The British blockade, which had effectively closed down German trade with the United States, was not able to prevent submarine travel. The Allies responded to this development with great concern and sent a note of protest to the US government, arguing that submarines should not be treated as merchant vessels, since they could not be inspected for weapons and ammunition in the same way ships could be. In Secretary of State Robert Lansing’s response, the United States held firm to its neutral stance, declaring that excluding a merchant vessel from trading because it is a submarine was unprecedented.

The German submarine Deutschland docked in Baltimore, Maryland, on July 9, 1916, after four weeks at sea. It was a merchant vessel carrying a cargo of medicine and dyes. Its arrival in the United States, still a neutral country, sent a message to the other warring European nations that Germany would be able to cross the Atlantic for supplies and repairs. The British blockade, which had effectively closed down German trade with the United States, was not able to prevent submarine travel. The Allies responded to this development with great concern and sent a note of protest to the US government, arguing that submarines should not be treated as merchant vessels, since they could not be inspected for weapons and ammunition in the same way ships could be. In Secretary of State Robert Lansing’s response, the United States held firm to its neutral stance, declaring that excluding a merchant vessel from trading because it is a submarine was unprecedented.

The United States struggled to maintain and enforce its neutrality during World War I. In the first months of the war, England’s vastly superior navy had choked off most trade with Germany; as a result, Germany focused on developing its fleet of submarines, known as Unterseeboots (“undersea boats” or U-boats). Although sometimes used against naval warships, U-boats were most often used to destroy merchant vessels and disrupt trade. Because they were most vulnerable at the surface, U-boats were often unable to ascertain the nationality and purpose of the ships they targeted, and cargo and passenger ships were sometimes destroyed; for example, in 1915, U-boats destroyed the British liner Lusitania, killing nearly twelve hundred people.

Submarines were able to avoid blockades; thus, the German government planned to use them to re-establish trade with the United States and other neutral nations. The Deutschland’s journey across the Atlantic illustrated that the British blockade could be circumvented, allowing supplies to be purchased in the United States. Germany was open about the mercantile purpose of its U-boats, declaring that “Great Britain cannot hinder boats such as ours to go and come as we please.”

Great Britain and its allies objected strongly to the landing of the Deutschland in the United States, arguing that neutral governments should take measures aimed at “preventing belligerent submarine vessels, whatever the purpose to which they are put, from making use of neutral waters, roadsteads, and ports.” Submarines were not able to be inspected, and, therefore, their status, as either commercial or military vessels, could not be determined; it was impossible to “remove the capacity for harm inherent in the nature of such vessels.” The Allies demanded that submarines be held in port and declared that, if a submarine were allowed to rest and refuel, the neutral port had become, effectively, a base of naval operations. This was strong language indeed and implied that the United States risked losing its neutral status. The Allies also warned that neutral submarines would be in grave danger in waters visited by belligerent submarines.

The United States, which had declared itself open to trade with all nations (but, in fact, had strong cultural and commercial ties with Great Britain), was under pressure from Germany to prove that it was indeed neutral. Germany also had goods that were valuable to the United States, and it responded to the Allies’ note of protest with an equally strong response. The United States argued that the existing rules of engagement governed by international law were sufficient to address the status of submarines and that it was surprised at how quickly the Allies sought to change these rules and threaten US neutrality.

The United States continued to trade with Germany throughout 1916. The Deutschland made a second trip to the United States that year, docking in New London, Connecticut, in November, with a valuable cargo of jewels and medicine. Also in 1916, the combat submarine U-53 crossed the Atlantic to Newport, Rhode Island, and sank several Allied ships on its return trip.

In January 1917, in an effort to bring the war to an end, Germany declared that it would wage unrestricted submarine warfare against all shipping vessels, neutral or belligerent. This brought about the end of US diplomatic and trade relations with Germany, and in the next two months, German submarines sank four unarmed American vessels. The United States finally declared war on Germany in April 1917.

Robert Lansing was born in Watertown, New York, in 1864. He was admitted to the bar in 1889 and became an authority on international law. Lansing helped found the American Society of International Law and the American Journal of International Law. President Woodrow Wilson appointed him to the State Department in 1914. After the sinking of the Lusitania in May 1915, Secretary of State William Jennings Bryan resigned because he felt that Wilson’s reaction was too belligerent. Lansing supported a strong response, and Wilson appointed him secretary of state in June 1915. Though a staunch defender of neutrality and the rights of US vessels at sea, Lansing came to believe in the inevitability of US involvement in World War I, and he was instrumental in securing both financial and military support for the Allies. He served as secretary of state until February 1920, after which he resumed practicing law. He died in Washington, DC, in 1928 at age sixty-four.

Lansing’s response to the Allied protest about the Deutschland docking in a US port addressed the Allies’ position that neutral countries should restrict access to their ports. The Allies noted the inherent dangers of submarines because such vessels’ position, threat level, and national origin were difficult to determine while at sea. Because of this, the Allies strongly urged neutral nations to hold submarines belonging to belligerents in port, insinuating that lack of compliance on the part of neutral nations would be considered naval support for the enemy, and, as a result, their own submarines would be subject to attack. Lansing expresses surprise that the Allies would seek to change international naval law, which is effectively what they were doing by excluding submarines from rules governing other vessels. More egregious was the implied Allied threat to neutral nations, such as the United States.

The United States believed that rules governing other types of vessels were sufficient to govern submarines; or, more specifically, the Allies had not given sufficient evidence that submarines should be excluded from existing rules. Most important, Lansing insists, American waters are neutral, and it is up the United States, not the Allies, to determine how to treat vessels in its ports. The United States reserved “its liberty of action in all respects” in American waters. Lansing reminds the Allies that the United States was not only neutral but also had “maintained those principles [of neutrality] in the traditional spirit and with the high sense of impartiality in which they were conceived” for over a century. In closing, in response to the Allies’ implied threat to neutral submarines, Lansing states that any “conflict that may arise between belligerent warships and neutral submarines” because of a belligerent warship’s failure to correctly identify the submarine would be entirely the fault of the warship.

US neutrality is the central theme of Lansing’s letter to the Allies. Belligerent nations from both sides were eager to leverage US power to their advantage. Though public opinion in the United States strongly favored the Allies, widespread support for entry into the war did not exist. President Wilson won reelection in 1916 with the slogan, “He kept us out of the war.” At the same time, American citizens demanded the right to travel safely at sea and looked to Wilson to protect that right through diplomatic means. When relations between the United States and Germany soured after the sinking of the Lusitania, it was particularly important that the United States make no definitive move leading to war.

If the United States had agreed to Allied demands that German submarines be held in port, Germany would have construed that as a clear act of hostility. The United States had defended the principles of neutrality since the beginning of World War I and had to apply them equally to Germany or risk losing its neutral status and the safety of its citizens.

• “Biographies of the Secretaries of State: Robert Lansing.” Office of the Historian. US Department of State, n.d. Web. 15 Jan. 2014.
• Carlisle, Rodney.Sovereignty at Sea: U.S. Merchant Ships and American Entry into World War I. Gainesville: UP of Florida, 2011. Print.
• Smith, Daniel Malloy.Robert Lansing and American Neutrality, 1914–1917. New York: Da Capo, 1972. Print.
• Tuchman, Barbara.The Guns of August. New York: Ballantine, 1962. Print.
• Tucker, Robert W.Woodrow Wilson and the Great War: Reconsidering America’s Neutrality, 1914–1917. Charlottesville: U of Virginia P, 2007. Print.