Question

Describe the movement from U.S. neutrality to engagement in World War I, with reference to unrestricted submarine warfare.

Answer 1

First, the US was anything but neutral in WW1. The US was shipping to Britian and France everything that was not nailed down. Half the rifles in the British Army were american made. Most of the steel used in the French armements industry was american, along with half the French TNT.

Britian and France offered insurance to any ship that carried munitions, so just about every American ship carried some contraban.
For the German, the one thing worse than american grain and armements to their enimies, while their workers were going hungry, was the threat of American soldgiers. So a agreement was reached with the US. The US promised not to sell rifles and hunting ammunition, and the Germans promised not to hunt more than 200 miles from Europe (restricted submarine warfare).

America did not stop shipping war goods. Under international law, a German submarine had the right to stop a ship, board it, inspect it, and destroy it if they found contraban. However Winston Churchill had armed some ships, called Q ships, which occatonally did fly the american flag. The submarine would surface, the american or british ship would announce to the world by radio that they were being boarded, so the British Navy would be arriving within an hour. If the ship was a Q ship, it would open fire, and sink the submarine.
Finally, in late 1916 the Germans had enough. If the Germans could cut off the flow of war material flowing from America, the Allies would collapse. America seeing a billion dollar trade would declair war, but it would take the US at least two years to field a million man army.

With unrestricted warfare, the Germans could attack a ship anywhere, preferably far away from the nearest allied warship. For the first few months of unrestricted warfare, it looked like it might work, but allied Navy's addapted with convoys accross the atlantic, made possible by the addition of American destroyers.