President Joe Biden’s administration has offered its answer to this problem: “integrated deterrence.” That concept has many facets, but its key tenet is that deterrence requires synchronizing all tools of American power — military, economic, diplomatic and otherwise — into a package of pain that no rival wants to suffer...it has real drawbacks, given that Russian President Vladimir Putin was not, in fact, deterred... After the Cold War, deterrence fell from this intellectual and policy prominence. One reason was that America’s military dominance meant that deterrence by denial seemed easy, even automatic: There was no question Washington could defeat China or Russia, let alone Iraq or Iran, in a major war. And deterrence got little thought in the war on terrorism because it seemed impossible: How does one deter a suicide bomber who is willing to die for his beliefs? This atrophy is no longer acceptable. Long-term military buildups by Russia and especially China have made wars in Eastern Europe or the Western Pacific a more frightening prospect. Moscow and Beijing appear to be laying plans to use nuclear weapons as tools of geopolitical revisionism, by threatening the U.S. and its allies with limited nuclear strikes if they intervene in wars of regional conquest. The inescapable challenge of this era is preventing autocratic powers from reordering the regions around them by force... The problem, though, was that not even Western officials knew how far they would go until Putin tried to erase Ukraine from the map. By the time that reaction came, deterrence had already failed. A second answer is that Washington botched the application of deterrent threats...But Biden’s declaratory policy — the effort to shape Putin’s incentives through precisely worded statements — has been a disaster. While it is undoubtedly important to avoid a great-power military showdown over Ukraine, removing any threat of American intervention simply ensured that Putin didn’t have to worry about matters getting out of hand. Similarly, Biden’s offhand remark that the allies would simply bicker among themselves in the event of a “limited incursion” was probably accurate — and it probably gave Putin hope that he could split the opposing coalition.