After looking into the war a bit more, it seems America would benefit from it. The U.S. wanted to take a neutral stance in the war, so couldn't trade with Germany as well Great Britain have made America an even greater superpower in addition to staying out of the war?
Yes, it did, and ironically, those attempts were a key cause to the start of unrestricted submarine warfare.
The British blockade of Germany foiled these attempts, but this blockade was extremely controversial in the United States before the sinking of the Lusitania started to shift public opinion.
Before the Lusitania, American public opinion was divided about the war, largely because the British blockade included the seizure of American ships. At the war's start, this included several ships carrying copper. These ships were taken in high-profile incidents that sparked outrage among many in the United States.
On Dec. 28, 1914, President Wilson reacted to this public opinion by sending an official note to Great Britain complaining that the blockade had seized ships carrying cargo to neutral countries in Europe and that it had seized "non-belligerent" cargo from ships bound for Austria and Germany. Here's an excerpt from the Associated Press report on the note:
"Almost the sole topic of conversation tonight in official and commercial circles was the note sent by the President to England.
From all over the United States have been received protests against what was termed the high handed methods of Great Britain in arbitrarily holding up American ships bound to neutral ports. These indicate that the President will be backed up in his stand."
On Jan. 7, 1915, Sir Edward Grey admitted that (at least when it came to food) that the British should not seize it without evidence that the cargo was bound for the enemy government or its military. He further said that the British government would adhere to that rule, but that the U.S. government should understand that there might be exceptions to it, given that Britain was currently fighting an enemy violating "hitherto accepted rules of civilization and humanity."
On Jan. 22, 1915, the American steamer Wilhelmina left New York City with $200,000 worth of food, bound for Germany. Thanks to the British response, this was a test case to determine whether Grey's note would hold true. Officially, the cargo was destined for an American in Germany.
Three days after the Wilhelmina's departure, the issue was complicated by a decree of the German Federal Council. In that decree, the German government assumed control of all food in Germany, and all grain and flour imported into Germany after Jan. 31 could only be delivered to organizations under direct government control. (The latter part of the decree was repealed on Feb. 6, but the letter and intent of the original decree remained clear.)
On Feb. 9, 1915, the Wilhelmina made port in Falmouth, England as a result of a storm that forced it to take shelter. With its arrival in port, the ship was seized by British authorities. The ship's owners duly protested, citing Grey's Jan. 7 note.
Grey in turn responded with the German declaration of Jan. 25 and mentioned the case of the Maria, a Dutch grain ship that had been sunk in September 1914 by the German cruiser Karlsruhe in the Caribbean while carrying grain to Ireland. Grey also responded that the Germans had bombarded Scarborough and Whitby under the belief that they were fortified towns and a base of operations for supplying troops in France. If Germany were to act that way, Britain had no choice but to do the same.
Grey agreed that the Wilhelmina and her owners would be paid for their inconvenience: The British government agreed to pay the Hamburg price for the ship's cargo, a fee for delaying the ship, and all expenses incurred.
A similar case took place with the steamer Dacia, a former German vessel that had been purchased by an American in January 1915. The Dacia left America for Rotterdam with a load of cotton about the same time as the Wilhelmina was being seized. On Feb. 28, 1915, the French government reported that a French cruiser had intercepted and captured the Dacia at sea and taken it to Brest.
At the beginning of February 1915, the German government issued its unrestricted submarine warfare order. Starting Feb. 18, 1915, the waters around Britain would become a "war zone" wherein any enemy merchant ship could be sunk without warning.
In response to the German action, on March 11, 1915, Prime Minister Asquith issued an unequivocal blockade order. He declared it was the intention of the British government "to divert all ships trafficking with Germany, and to take them into port, though without confiscating either ship or cargo, save where they would otherwise be liable to confiscation."
Asquith's order deliberately omitted the terms "blockade" and "contraband" because those were legal terms with specific meaning, and they could inflame the United States. Instead, his order was a de facto blockade, even if he didn't outright say it. American ships would be diverted from their courses, but they would be compensated for their trouble and returned to their owners.
Trade, for all intents and purposes, was closed with Germany for the rest of the war.
The story of the Wilhelmina has an ironic and sad ending. On May 8, 1915, as she sailed from Leith to Fowey in ballast, she was torpedoed by the German submarine U-9 about 20 miles southeast of Longstone. Her captain beached her and saved every member of her crew, but the ship was a total loss.
Edit: Read The Law of Contraband of War for more details on this topic.
Yes America and Germany traded before becoming enemies. It was however made difficult by the Royal Naval blockade of Germany.
In response Germany built a trade submarine and sailed across the Atlantic, the first time such a journey was made. The German crewman were greeted as heroes when they arrived in New York, however the journey had been horrendous. Rough seas meant the vessel was submerged longer than intended, and it was noisy, cramped and hot. All surfaces and food were covered in a thin film of diesel from the engines.
They returned with a cargo of nickel, tin, and rubber that Germany desperately needed. However the cargo was too small to make a real difference to the war effort. It was however a psychological victory for the surrounded Germans.
Technically yes, however the British blockade prevented this. The Germans eventually even sent a merchant submarine to the US to trade in 1916. This came to a halt when the US entered the war.
