As the North Korean army slashed its way down the Korean Peninsula in 1950, 15-man units infiltrated South Korean lines to ambush convoys and demolish bridges.
America sought to respond in kind, forming Ranger units with skills like low-altitude parachuting and sabotage.
Americans fell in love with these elite warriors. One reporter wrote that each Ranger “is a one-man gang who can sneak up to an enemy sentry, chop off his head, and catch it before it makes noise by hitting the ground.”
The country, and its presidents, have been enamoured with special operations forces ever since Franklin Roosevelt created the first unit in 1942.
John F. Kennedy expanded the Army Special Forces from 2,000 to 10,500 soldiers and founded the Navy SEALS.
Under George W. Bush and Barack Obama, special operations forces grew from 38,000 in 2001 to 70,000 in 2016.
Will President Donald Trump follow suit?
He has already used special operations forces in several Middle Eastern countries. And the units seem custom-made for a president intent on both combating terrorism and avoiding large-scale war.
But the history of America’s special operations forces recommends caution. They are primarily tactical tools, not strategic options. Nor, for all the talent and training, can they always beat the odds.
When Jimmy Carter sent special operators to rescue the hostages in Iran, the raid went awry far short of its objective, with eight dead Americans left behind.
Bill Clinton deployed Delta Force members to neutralise the Somalian warlord Mohamed Farrah Aidid, but aborted the mission after militiamen dragged American corpses through the streets of Mogadishu. Barack Obama’s use of special operations forces to train a Syrian rebel army yielded a pitiable “four or five” fighters.
When special operations forces have succeeded tactically — as they so frequently and impressively have — they rarely have produced strategic success on their own.
Bush and Obama hoped that precision strikes by special operators would decapitate the insurgencies in Iraq and Afghanistan, but the insurgents endured so long as they controlled territory and population.
The killing of Osama Bin Laden did not cripple Al Qaida, and it produced a strategically damaging backlash in Pakistan.
With the notable exception of the defeat of the Taliban in 2001, strategic victory has required the integration of special operations forces with both conventional forces and civilian national security agencies.
It’s also uncertain how relevant special operations forces will be in the next war. Although Trump may not be interested in fighting a major war, he may be left with little choice.
Lyndon Johnson sent US troops into Vietnam in 1965 after campaigning as the peace candidate in 1964. George W. Bush became enmeshed in counterinsurgencies in Afghanistan and Iraq despite a vow to keep the nation out of such quagmires.
America’s special operations troops can hunt down a terrorist or train an elite unit better than anyone. But they can’t destroy a Russian armoured division or occupy a North Korean city.
If the military continues to shift talent from conventional to special units through expansion of the latter, the conventional forces required in a large war will suffer.
One virtue of the military veterans in Trump’s national security circle is their ability to reject the unrealistic expectations of military novices, a group that has always been well represented among the White House consiglieri.
The deployment of Marines to Syria last month is an encouraging sign of a willingness to transfer burdens from special units, overutilised by Obama-era greenhorns, to underutilised conventional units.
Let’s hope it represents a trend. If Trump pays heed to the generals and the veterans, he is likely to go down in history as one of the few presidents to demonstrate sobriety and prudence in the use of Special Operations forces.
Mark Moyar is the director of the Centre for Military and Diplomatic History and the author of the forthcoming ‘Oppose Any Foe: The Rise of America’s Special Operations Forces’.