If Spain tanks, then all of Europe is screwed; therefore, Spain cannot be allowed to default. What this means is that Spain holds all of the cards.
Let’s say Spain refuses to request a bailout under any circumstances. It’s options are either a hard default where it stops paying back its debts or a devaluation default where it reverts back to its national currency, the peseta. Either option spells disaster for the rest of Europe and particularly Germany.
Spain will play chicken with Germany throughout September until Germany relents and either writes a check with minimal strings attached or allows the ECB to begin monetizing the debt.