Final answer:
Bismarck consolidated his domestic policy through the Dual Alliance by securing Austria-Hungary's support in case of conflicts with Russia.
Step-by-step explanation:
Otto von Bismarck consolidated his domestic policy through the dual alliance by strengthening Germany's position and protecting it from potential threats. The Dual Alliance was an agreement between Germany and Austria-Hungary that aimed to stand up to Russia. By forming this alliance, Bismarck ensured the support of Austria-Hungary in case of any conflicts or aggression from Russia, thus consolidating his domestic policy of maintaining Germany's power and security.