Bait and bleed

Bait and bleed is a military strategy described by international relations theorist John J. Mearsheimer in his book on offensive realism, The Tragedy of Great Power Politics. The aim is to induce rival states to engage in a protracted war of attrition against each other "so that they bleed each other white", while the baiter who encouraged the conflict remains on the sidelines, maintaining its military strength.

Mearsheimer cites as an example Russia's efforts to provoke Austria and Prussia into war with France shortly after the French Revolution, evidenced by Catherine the Great's statement to her secretary in 1791, "I am racking my brains in order to push the courts of Vienna and Berlin into French affairs...There are reasons I cannot talk about; I want to get them involved in that business to have my hands free. I have much unfinished business, and it's necessary for them to be kept busy and out of my way."

Mearsheimer describes a similar strategy which he calls "Bloodletting" which does not involve incitement or baiting by a third party. When a state's rivals have gone to war independently, the aim is to encourage the conflict to continue as long as possible, in order to let the rival states weaken or "bleed" each other's military strength, while the bloodletting party stays out of the fighting.

This strategy is exemplified in then-U. S. Senator Harry Truman's statement in 1941 regarding the Nazi invasion of Russia, "If we see that Germany is winning we ought to help Russia, and if Russia is winning we ought to help Germany, and that way let them kill as many as possible."

Another example of this strategy was Soviet Russia's withdrawal from World War I while the fighting in Europe between Germany and the remaining Allies continued. In his report to the Third Congress of Soviets in 1918, Vladimir Lenin argued that by withdrawing from the conflict "we rid ourselves...of both imperialistic groups fighting each other. We can take advantage of their strife...and use that period when our hands are free to develop and strengthen the Socialist Revolution."

...
Wikipedia