A credible deterrent is designed to alter a potential aggressor’s calculations of risk and reward. Vladimir Putin determined that the potential cost of invading Ukraine was relatively low, and on Feb. 24 he attacked. It will be the job of historians to try to understand why deterrence failed. Deterrence involves two factors: capability and will. Capability means having the military strength to deliver intolerable damage to an adversary. Will is the determination to use that strength and deliver that damage. .....snip..... By signaling that the U.S. had no intention of using its capabilities, the Biden administration seriously weakened their deterrent...