The degree of his involvement in the events leading up to the outbreak of World War I is a matter of keen debate, with some historians putting the blame for an early and provocative mobilization squarely on Sazonov's shoulders, and others maintaining that his chief preoccupation was "to reduce the temperature of international relations, especially in the Balkans".

Notwithstanding the promising beginning, the Russian-German relations disintegrated in 1913, when the Kaiser sent one of his generals to reorganize the Turkish army and to supervise the garrison in Constantinople on request of the Ottomans, remarking that "the German flag will soon fly over the fortifications of the Bosphorus", a vital trade artery which accounted for two fifths of Russia's exports.

In the run-up to a major military conflict in Europe, another concern of the Russian minister was to isolate Austria-Hungary, mainly by playing the Balkan card against the supposedly-dwindling power of the Habsburgs.

[5] While extremist agents like Nicholas Hartwig aspired to solidify the conflicting South Slavic states into a confederacy under the aegis of the Tsar, there is no indication that Sazonov personally shared or encouraged these views.

Regardless, both Austria-Hungary and Germany were persuaded that Russia fomented Pan-Slavism in Belgrade and other Slavic capitals, a belligerent attitude in some measure responsible for the Assassination in Sarajevo and the outbreak of the Great War.

"[6] As World War I began, Sazonov worked to prevent Romania from joining the Central Powers and wrested in March 1915 an acquiescence from Russia's allies to the post-war occupation of the Bosphorus, Constantinople, and the European side of the Dardanelles.

Sazonov was viewed favourably in London, but the Germanophile[8] faction of Tsarina Alexandra fiercely urged his dismissal, which did materialize on 10 July 1916[9] after the minister had aired a proposal to grant autonomy to Poland.