Central Banks at War

War is expensive—troops must be equipped and weapons must be procured. When the enormous borrowing requirements of war make the sovereigns' credibility problem more difficult, central banks enhance a government's ability to borrow. By being the sole direct purchaser of government debt, the central bank increases the effective punishment that can be imposed on the government for defaulting on the marginal lender. This increases lenders' confidence that the government will be punished in case of default, making lenders willing to purchase the debt at a lower rate of interest. The sovereign, dependent on the low borrowing costs offered by the central bank, has an incentive to retain the bank. Data covering the nineteenth and early twentieth centuries reveal that possessing a central bank lowers the sovereign's borrowing costs, particularly during times of war.