Once Bulgaria quit the war, the dominoes began to fall. By early October, both Germany and Austria were in diplomatic exchanges with the US over peace terms. When news of this became public, both of those governments experienced domestic political collapse.
The German commanders and their African askari soldiers fought a smart and determined guerilla campaign against the British that actually lasted longer than the war in Europe had. But when news of the Armistice reached them, it was time to lay down their weapons.
The German spring offensives of 1918 were intended to force an end to the war before Allied numerical superiority became decisive. But the offensives failed, the German Army is crumbling, and mobile warfare has returned to the Western Front.
It was poetic that the war would end where it began, in the Balkans. An Allied offensive against a weary Bulgaria led to an armistice, forcing the Ottoman Empire--and Austria and Germany--also to sue for peace.
The policies of the new Bolshevik government befuddled both the Allies and the Central Powers. Both sides in the war sought better relations with Moscow, but the murders of the Imperial family signaled that the Bolsheviks were not ready to make nice.
The end of the war on the Eastern Front and the Italian defeat at Caporetto gave Austria-Hungary a badly needed military respite. But domestically, the country was crumbling, economically, socially, and politically. Discontent has reached critical mass.
The length and the toll of the Great War were a tragedy, but for Czech and Slovak nationalists, they also presented an opportunity to shake off the bonds of Habsburg rule and achieve independence.
In Russia, the Bolshevik government succeeds in throttling the Constituent Assembly and taking full control of the national government. They find themselves up against an array of enemies, including Czech and Slovak soldiers who had been fighting in the Russian Army.
A year after the US declared war on Germany, America's contribution to the war effort was still small. Later in 1918, after working through some political and organizational difficulties, American units began to make a difference on the battlefield.