American doughboys on the Italian Front in World War I. Credit: U.S. Army.

Freedom doesn't come easy. Ask the sergeant helping train an Iraqi infantry battalion who, four tours and ten long years ago, was a young private conducting weapons searches in Baghdad's slums. Perhaps a soldier struggling to keep the HMMWV trucks in his unit's motor pool running in spite of the choking dust of southern Afghanistan might have some thoughts on this, or a 2nd Infantry Division trooper forward deployed near the Demilitarized Zone separating a vibrant South Korea from the misery that is North Korea. Ask a veteran of Vietnam, Korea, or World War II -- whose numbers grow ever smaller.

From the earliest days of the republic through to the dawn of a new century, the number of young men, and in recent times, women, who have worn the uniform of the United States Army -- be it blue-dyed wool, khaki cotton, or a modern "battle dress uniform" -- has reached into the tens of millions. Yet even during the "big" wars, the Army has always been a force stretched painfully thin. When not fighting the British and the Mexicans during the seven decades between the Revolution and the Civil War, the size of the Army generally averaged about five to six thousand men before the numbers gradually floated up into the range of about nine thousand. After the Civil War and Reconstruction the number of soldiers spread from seacoast garrisons to isolated frontier forts hovered in the narrow range of twenty-six to twenty-eight thousand. And all of these totals are, frankly, on the high side as desertion and death-more often from sickness than combat took their toll.

After the Spanish-American War, the size of the Army fluctuated wildly but only once dipped below 65,000 as new possessions -- stretching from the Caribbean and Panama Canal all the way across the Pacific to the Philippines -- and growing storm clouds in Europe required a larger and more professional force. It was more than twice this size between the world wars, but still considered small and ineffectual by the great powers of Europe and even the Asian littoral. After the next global war, the Army quickly shed more than six million men, and though it would never again be required to raise and sustain such a massive force, its ranks would swell and deflate time and time again for wars along Asia's periphery. Throughout it all, the United States Army, a mixture of both professional and citizen soldiers, never failed its fellow Americans.

The secret of the Army's success is, in many ways, not a secret at all. Although its "body" is plain for all to see-personnel, weapons, bases-what makes it an army and not a well---armed mob ready to dissolve under the stress of combat, is its "soul"---an intangible flame called esprit de corps, the unity of purpose and will to win that is fundamental to victory. Leadership, training, and discipline instilled in America's soldiers is all undergirded by an institutional culture that is fundamentally historical in nature. The Army cherishes its past, especially its combat history, and units preserve their histories, proudly displaying them in crests, patches, and regimental mottoes. Ceremony and custom nourish the army's institutional memory, and its traditions reinforce this esprit de corps and the distinctiveness of the profession.

Yet even esprit de corps goes only so far. An army of both professional and citizen soldiers -- a national army -- is affected in fundamental and profound ways by the character of the nation and the will of its people to resist the forces that would destroy it. Since its founding, the United States Army has often been severely tried by the indifference, and even hostility, of many of those it protects. But the Army did, and does, persevere. As it always has, it salutes smartly and its soldiers do their duty, all while upholding the highest ideals of the nation's founders.

As each generation of soldiers came forth and then faded away, the exhilaration, the terror, the crushing boredom and frustrations of soldiering in war and peace passes inexorably from living memory as America rushes on to its destiny. Throughout it all, more men, and now women, have stepped up. At different times in our nation's history they have entered the army through the compulsion of a military draft. More often they have volunteered, as four generations of Americans have since U.S. forces left Vietnam in 1972 when volunteers alone supported a Cold War Army averaging more than three-quarters of a million active duty soldiers for nearly two decades.

During the first battles of the twenty-first century, some supporters of the armed forces and the war against the trans-national Islamic extremists who attacked America warned that the nation's now shrunken Army could break under the strain of a two-front war. Meanwhile, critics and pundits confidently predicted that enlistments would dry up and that National Guardsmen -- who they imagined had "only joined for the benefits" -- would flee the service when their terms were up now that they were actually being sent off to fight.

None of this happened. Young Americans stepped up yet again by the tens of thousands, year in and year out, to enlist and reenlist, into the active Army, Guard, and Army Reserve, knowing full well what lay ahead. In the second-longest war in our nation's history, victory was achieved in Iraq, and the fight still goes on to ensure that Afghanistan never again becomes a sanctuary for those who would attack America.