Ultimately, the European collaborators remained subordinated to German oversight and were "kept on a short leash."[11] Rolf-Dieter Müller puts the figures for the European Wehrmacht allies and volunteers who fought in the eastern campaign at approximately one-million men in total, which he claims gives substantial reason to "re-evaluate" the "military dimensions" of the overall collaboration.[12] In Müller's estimation, the Wehrmacht would not have been capable of making it to Moscow in 1941 were it not for the Finnish, Hungarian, and Romanian conscripts; operations in the Volga and Caucasus in 1942 would have ground to a halt without the additional forces; and following the disaster at Stalingrad, it was foreign conscripts and volunteers (60,000 troops) fighting partisans in the Balkans which enabled the Germans to stabilize the Eastern Front in Finland and the Ukraine.[13] Müller also carefully reminds readers that on top of the co-opted aide of collaborators, millions of foreign laborers were forced to help provide the Nazis with the needed material resources to carry on the war far longer than otherwise possible without their toils.[13]