The most significant development of the Hundred Days Offensive was Russia's
withdrawal from the war in the spring of 1918. The Russian Revolution, sparked
by Russia's mismanagement of the war, resulted in Vladimir Lenin's' Bolshevik
Party coming to power. Russia reached a peace agreement with Germany by ceding
Finland, the Baltic provinces and parts of Poland and Ukraine to the Central
Powers. Germany's attempts to manage and exploit its new lands decreased its
ability to punch forward on the Western Front.
Meanwhile, Germany was also being choked by a British naval blockade. The
blockade (and other Allied sea traffic) was at first threatened by German submarines
but the British soon learned to use convoys to protect themselves.
Another key development was the introduction of American troops into the war.
Early in the Great War America had taken an "isolationist"
position. But, when Germany ramped up its submarine
attacks and encouraged Mexico to join forces with it against America, U.S. President
Woodrow Wilson declared war on Germany on April 6, 1917. By the spring of the
following year, enough American forces were on the ground in France to support
the Allies' push back against the Central Powers' Spring Offensive.
Finally, by the first days of the final offensive, the British had sufficient
tanks and guns to strike at a number of places along the Western Front at the
same time. This allowed the Canadian Corps to move easily from Amiens, back to
Arras and through the Hindenburg Line.