Historical parallels are never exact. So, looking back to the 1930s may not be relevant to dealing with the Islamic State today. Or perhaps it would be relevant. During 1935-40, Britain was led by Prime Ministers Stanley Baldwin and Neville Chamberlain. England and France were still haunted by their huge losses of life in World War I. Their economies were mired in a prolonged depression. The names of Baldwin and Chamberlain are not cited to suggest the ghost of appeasement; rather the ghost of missed opportunities to treat a threat in a timely manner.

In Mein Kampf, published in 1925-26, Adolf Hitler had penned a lengthy, semi-autobiographical political tract, which was not taken seriously by most political elites, even after he came to power in January 1933. Its main messages were the goal of achieving “Greater Germany” by uniting German-speaking peoples, and a consuming hatred of Jews. After Hitler’s ascension to power, he brutally established an absolute dictatorship, gradually stripped Jews of their rights and economic resources, and undertook an ambitious program of rearmament. At the same time, England was devoting scant resources to strengthening its military preparedness. There were lone voices, most prominently the voice of Winston Churchill, who saw the signs of German rearmament as they were occurring and warned of the dangers of Hitler’s Germany. Churchill was largely ridiculed and ignored.

In March 1936, Hitler violated the Versailles and Locarno treaties and sent troops into the Rhineland. Had the large French army entered the Rhineland to chase out Hitler’s troops, an easy victory would have been realized, probably leading to Hitler’s loss of power. An opportunity not seized. Hitler had read correctly the enormous reluctance of those in power in England and France to use force, and he got away with it.

Hitler’s absorption of Austria came next in March 1938. He reassuringly claimed that he had no other territorial ambitions, and Chamberlain’s government chose to believe this. Hitler’s next target in the summer of 1938 was the largely German-speaking Sudetenland part of Czechoslovakia. Much of Czechoslovakia’s border with Germany had favorable defensive features, which were enhanced by strong fortifications built by the Czechs as fears about Germany rose in the 1930s. Czechoslovakia also had a large, well-trained army. In post-war testimony, several German generals stated that a German attack on Czechoslovakia in Autumn 1938 likely would have failed. Thus, if there had been no appeasement at Munich, which ceded the Sudetenland to Germany, the Germans might have been stopped at the border of Czechoslovakia. Another opportunity lost. The new border of Czechoslovakia was a weak one militarily. The rest of Czechoslovakia fell to Germany in March 1939.

The steady expansion in 1938 and 1939 of Germany’s armed forces and industrial might, the latter enhanced by its effective control of Austria and Czechoslovakia, and the weak rearmament response of England, set the stage for initial German dominance following the outbreak of World War II in September 1939. In the resulting long war, tens of millions died, including, the millions of European Jews murdered in the Holocaust.

In 2014, seemingly out of nowhere, the Islamic State has made stunning gains in strength and territorial control of parts of Syria and Iraq. In its sweep forward it has committed numerous killings and other atrocities against soldiers and civilians. It openly proclaims its aim for domination over large areas of the globe and its hostility to the West. Such grandiose plans are a kind of parallel to Mein Kampf.

After months of US inaction and President Obama’s dismissal of the Islamic State as inconsequential, the US initiated airstrikes in early August in response to urgent Islamic State threats against ethnic minorities and key Kurdish positions. But, only after the gruesome beheading of American journalists James Foley and Steven Sotloff did Obama declare that the Islamic State is to be destroyed. The President is now working to assemble a multinational coalition of states for this purpose.

Today, the Islamic State is still small and weak in comparison to the armed forces, technology, and resources of the United States. A direct confrontation on the ground as well as in the air might lead to the early destruction of the Islamic State. However, the US remains supremely reluctant to contemplate such ground action, due to its negative experiences in the wars in Iraq and Afghanistan. In recent days, Obama, Kerry, and Biden all stated that a condition of any plan to destroy the Islamic State is “No American boots on the ground.” This gut aversion seems to parallel the British and French attitudes about using force in the 1930s. Maybe other boots can be found to do the job, with US air support and indirect assistance. One hopes so.

But perhaps that won’t do it. Maybe the monster that is the Islamic State will absorb its present conquests, attract new adherents from abroad, attack new targets, and, in general, become a more threatening entity during the coming months and years. One nightmare is that we will wake up one day, perhaps after a major attack by the Islamic State in Europe or even in the United States, or perhaps after an attack with unconventional weapons, and realize that the West missed the chance to end this horror at its early stages, much as England and France did with Hitler’s Germany in the 1930s.

But the Islamic State is hardly the only or even the largest threat in the Middle East. The Islamic Republic of Iran is an ideologically-driven country that seeks to expand its regional hegemony, is a sophisticated practitioner of terrorism, is hostile to the West, and threatens Israel. The fear of missed opportunities should hover over US policy decisions on Iran’s nuclear program as well.