What nation joined the Allied war effort in 1917? What nation dropped out of the war in 1918? How did these two changes affect the war?

There were
some significant changes in the countries fighting inin 1917 and in 1918. In 1917, the United
States entered World War I. The United States was upset with German actions, especially with the
German resumption of unrestricted submarine warfare. This action violated the American right as
a neutral nation to trade with other countries during the war. The Americans were also not
pleased that Germany tried to get Mexico to attack the United States, which was revealed in the
Zimmermann Telegram. The entrance of the United States was a huge boost for the Allies. The
Allies were struggling in their fight against the Central Powers. When the United States entered
the war, it brought fresh, rested troops to help the Allies fight. The United States was also
able to bring needed supplies and equipment to help the Allies in the war effort. It is fair to
say that the American entrance into the war was the decisive factor in the Allied
victory.

In 1918, Russia left the war. The Russian people were unhappy with
the rule of Czar Nicholas II, especially with the extreme poverty many people faced. There also
was discontent over the losses the Russian military experienced in the war. As a result, the
Russian Revolution began leading to a new government assuming power. With the signing of the
Treaty of Brest-Litovsk, the Russians stopped fighting in the war. This was a huge concern for
the Allies because the Germans no longer had to fight a two-front war. Germany could move more
of its troops to the western front, making it more difficult for the Allies to win the
war.

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