As Greece was highly vulnerable to the Allied navies and thus unable to openly side with the Central Powers, Constantine and his supporters argued for firm and "permanent" neutrality. The thinking of Streit, the King's main political advisor on the subject, was influenced by his fear of pan-Slavism (in the first instance Bulgaria, but ultimately represented by Russia), against which Germany supposedly fought, as well as by his belief that the traditional European balance of power would not be upset by the war, leaving little room for territorial gains by Greece in the event of her participation in the conflict. In particular, and in contrast to Venizelos, Streit believed that even if they won, the Allies would respect the territorial integrity of both Austria–Hungary and the Ottoman Empire. In addition, the King and his military advisors regarded the German army as invincible, while their differences with Venizelos exposed far deeper ideological divergences in Greek society as well: Venizelos represented the middle-class, liberal parliamentary democracy that had emerged after 1909, whereas the King and his supporters represented the traditional elites. Constantine was profoundly impressed by German militarism, Streit was a major proponent of royalist and conservative ideas, while the highly influential Chief of the General Staff Metaxas—who as dictator of Greece in 1936–1941 presided over a Fascist-leaning authoritarian regime—was already toying with proto-Fascist ideas. This disagreement became evident as early as 6 August, when Streit clashed with Venizelos and submitted his resignation. Venizelos refused to accept it so to avoid a political crisis, while the King also urged Streit to retract it, for fear that his replacement would allow Venizelos to push the government even further towards a pro-Allied course. Thus, when on 25 July the Serbian government requested Greece's aid under the terms of their alliance, Venizelos replied on 2 August that Greece would remain a friendly neutral. The Greek prime minister argued that an important clause in the alliance agreement was rendered impossible: Serbia had undertaken to provide 150,000 troops in the area of Gevgelija to guard against a Bulgarian attack. Furthermore, if Greece sent her army to fight the Austrians along the Danube, this would only incite a Bulgarian attack against both countries, which possessed insufficient forces to oppose it. On the other hand, Venizelos and King Constantine were in agreement when they rejected a German demand on 27 July to join the Central Powers.