The Treaty of Björkö lived its brief shimmering day, and expired

From The Guns of August by Barbara Tuchman.

When he failed, under the circumstances, to wean Russia away from France, the Kaiser drew up an ingenious treaty engaging Russia and Germany to aid each other in case of attack, which the Czar, after signing, was to communicate to the French and invite them to join. After Russia’s disasters in her war with Japan (which the Kaiser had strenuously urged her into) and the revolutionary risings that followed, when the regime was at its lowest ebb, he invited the Czar to a secret rendezvous, without attendant ministers, at Björkö in the Gulf of Finland. William knew well enough that Russia could not accede to his treaty without breaking faith with the French, but he thought that sovereigns’ signatures were all that was needed to erase the difficulty. Nicholas signed.

William was in ecstasy. He had made good the fatal lapse, secured Germany’s back door, and broken the encirclement. “Bright tears stood in my eyes,” he wrote to Bülow, and he was sure Grandpapa (William I, who had died muttering about a war on two fronts) was looking down on him. He felt his treaty to be the master coup of German diplomacy, as indeed it was, or would have been, but for a flaw in the title. When the Czar brought the treaty home, his ministers, after one horrified look, pointed out that by engaging to join Germany in a possible war he had repudiated his alliance with France, a detail which “no doubt escaped His Majesty in the flood of the Emperor William’s eloquence.” The Treaty of Björkö lived its brief shimmering day, and expired.