As the war in Ukraine continues into its third year of fighting, all parties appear more willing to escalate than to bring it to an end. In his annual “State of the Nation” address, President Vladimir Putin warned NATO nations that they “must, in the end, understand all this truly threatens a conflict with the use of nuclear weapons, and therefore the destruction of civilization,” if they continue to arm Ukraine and consider sending troops. Even as far back as June 2022, Putin warned U.S. officials against sending long-range missiles to Ukraine, stating, “We will strike at those targets which we have not yet been hitting.”

However, American policymakers and analysts seem to think that Putin won’t put his money where his mouth is when it comes to escalation. Adam Kinzinger and Ben Hodges assured readers that Putin is bluffing with his threats of nuclear escalation. NATO’s Secretary General, Jens Stoltenberg, dismissed the likelihood of Western aid to Ukraine leading to Russian retaliation. The Biden administration seems to agree, having recently allowed Ukraine to use U.S. weapons to strike inside Russian territory—a red line the administration previously refused to cross.

In this view, escalation is calculable, and countries tend to bluff with their red lines. This assumption is false. As the famed military and nuclear strategist Bernard Brodie explained, countries usually do not usually bluff when they make threats. In fact, there are multiple cases throughout history that show how this misunderstanding of escalation has led to disastrous results.

Japan’s logic behind its attack on Pearl Harbor is one such example of miscalculating an adversary’s willingness to escalate. At the time, Admiral Isoroku Yamamoto, the architect behind the attack on Pearl Harbor, believed this attack would destroy America’s morale, preventing America from countering Japan’s expansion of power throughout the Pacific. Ultimately, Japanese military thinkers sought to use Pearl Harbor as a way to shock the United States into a negotiated settlement with Japan. Of course, these expectations were way off the mark. The attack on Pearl Harbor instead brought America into World War II.

The Korean War provides another example of the costs of policymakers and military leaders ignoring red lines. In 1950, General Douglas MacArthur, the leader of the United Nations Command, pushed American-led forces up the Korean peninsula in a stunning counterattack against the North Korean military. In his book, The Korean War, Max Hastings details how MacArthur insisted on using American forces to achieve a complete victory against the North Koreans. This meant driving all the way up the Korean peninsula to the Yalu River—the geographic border between Korea and China. However, Chinese officials made it clear to American and UN officials that they should not push their forces past the river. American intelligence reports also showed that PLA military forces were mobilizing in the regions adjacent to the Yalu River. Still, MacArthur insisted that the Chinese would not enter this war. MacArthur’s assessment proved wrong, with Chinese forces pouring into Korea in October 1950, marking one of the turning points in the Korean War.

Soviet premier Nikita Khrushchev’s decision to send nuclear missiles to Cuba in 1962 is another example. On September 13, 1962, U.S. President John F. Kennedy warned the Soviet Union against turning Cuba into “an offensive military base of significant capacity.” However, Khrushchev called Kennedy’s “bluff” and decided to send medium-range nuclear missiles to the island. He viewed Kennedy as a weak leader and predicted that his administration would not do anything to counter this maneuver. While these missiles did not change the nuclear balance between the Soviet Union and the United States, in the eyes of the Kennedy administration, they threatened the credibility of America’s resolve. What followed from Khruschev’s missteps was the Cuban Missile Crisis—a tense thirteen-day period where two nuclear superpowers brought the world to the brink of nuclear Armageddon. Thankfully, the crossing of this red line did not result in military action, though we came far too close.

The moral of this story: it is difficult to tell if a country is bluffing. Case after case, the negative consequences of leaders downplaying the credibility of red lines are evident. Leaders of countries view credibility as an important factor in statecraft, especially when it comes to the concept of deterrence. As the economist Thomas Schelling wrote, the effectiveness of deterrence depends on “the power to hurt.” He continues with an even more telling point: “Unhappily, the power to hurt is often communicated by some performance of it.” In other words, deterrence only works if the other side believes that the other will do what they say. If red lines aren’t taken seriously, a country will act upon its threats to demonstrate its credibility.

American policymakers and analysts today should exercise caution in interpreting Russian signals. Far too many are calling on the United States to plow through Russia’s red lines and continue its salami-slice escalation over the Ukraine conflict. It is important to note that there are cases throughout history where a country did not escalate a conflict or crisis after an adversary crossed its red line. With Russia’s enormous arsenal of nuclear weapons, however, it would be a risky gamble for American policymakers to assume that Russia would not eventually escalate. As Carl von Clausewitz observed, “In the whole range of human activities, war most closely resembles a game of cards.” With stakes this high, America should be cautious, lest it lose all its chips.

Benjamin Giltner is a DC-based foreign policy analyst with a Master’s in International Affairs from the Bush School of Government and Public Service at Texas A&M University.

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