Who bore responsibility for the start of World War I?

Germany coerced their ally, Austria-Hungary, to begin conflict

Question: Who bore responsibility for the start of World War I?
Position‹2 of 4›: Germany alone is responsible
Argument1 of 2›: Germany coerced their ally, Austria-Hungary, to begin conflict

Without the coercion from Germany, Austria never would have gone through with retaliation following the Assassination. As the only war to have been caused by assassination, Germany was certainly whispering to provoke an overreaction.

The argument

Bethmann-Hollweg, Chancellor of Germany, essentially handed Austria-Hungary a "blank cheque" following the initial insurrection caused by the assassination of Archduke Ferdinand. This gesture signified to Austria that if they choose a path of conflict, Germany would support them and provide limitless resources to them in order to comfortably win and secure political triumph by fighting for the Balkans. Additionally, by providing this complete and absolute support for their ally, Germany could virtually advocate for themselves. They could insert their interests into a smaller conflict through offering support, but then expand it into a mass conflict of greater stakes and opportunity for both themselves and Austria-Hungary.

Premises

[P1]After the assassination of Archduke Ferdinand, Germany's Chancellor handed Austria-Hungary a blank cheque of limitless support for conflict. [P2] This signalled that Germany would back Austria's path to war to secure political triumph in the Balkans. [P3] Through that absolute support Germany could insert its own interests, expanding a smaller conflict into a mass war. [C] Therefore, because Germany coerced its ally Austria-Hungary into beginning the conflict, Germany alone is responsible for the start of World War I.

Counter-arguments

It can be argued that Germany persuaded Austria, but this does not change the role of Austria in the war and the state of affairs between Austria and Serbia. Without the Austrian/Serbian conflict, the War would not have incited and employed as many world powers as it had. Therefore, Germany can not be named the sole responsible actor.

Rejecting the premises

[Rejecting P1] Assurance of support is not coercion. The premise names the "blank cheque" and then reads it as compulsion, when Vienna had already resolved on action against Serbia and sought backing for a course it wanted. [Rejecting P2] What the signal encouraged was a local war, and Berlin's expectation of a contained Balkan conflict is well attested — so the inference to a design for general war does not follow from the encouragement described. [Rejecting P3] Even granting German ambition, "alone" is what the conclusion needs and the premise cannot supply it: Austria-Hungary issued the ultimatum and declared war, Russia mobilised, and the alliance obligations and mobilisation timetables of several powers turned a regional crisis into a European one — which is what the rival positions in this debate identify.