Its the sound of freedom, but you feel it before you hear it. Thats the jet noise of the F-18 fighter planes that roared overhead yesterday at the U.S. Naval Academy (USNA) in Annapolis, Maryland. The jets came in low. Their flight marked the induction of a new class of Midshipmen. The two fighters were piloted by Naval Academy graduates, and they flew up from the Naval Air Station in Oceana, Virginia. These flyovers are meant to inspire awe, and they do.

Induction Dayor I-Dayis the day when more than 1200 young people from all over the U.S. begin their Navy service. Male or female, theyre all Midshipmen. While most high school grads are working or enjoying this last summer before college, these Midshipmen are going through a rigorous eight weeks of what is called Plebe Summer. My wife Kate is a retired Navy Medical Service Corps captain. Weve been going to I-Day since 1997, when Kate was running the USNA health clinic.

Physical exams are a big part of I-Day. Captain Morrisons 250 military and civilian staff would all turn out to supervise the in-processing of the new class. All the medications the Plebes brought with them are collectedeven aspirin and Visineand dumped in a big pile. From then on, only Navy-prescribed medications could be carried or consumed. The Plebes would be poked and probed by Navy docs, checked for a host of diseases or disabling conditions.

Theres some tension in the day. Tragic tales are told. One young man whose father and grandfather, like those of John McCain, were Academy graduates was found to have a previously undetected heart murmur and had to be turned away.

The overwhelming majority of the Class of 2013, though, are healthy as horses. The young mens heads are shaved; the young women get a short bob. They all wear white worksbaggy white jumpers and pants with white Dixie cup caps circled by a distinctive blue band. Theyll all be required to carry water with them at all times during the usually hot and humid summers of Annapolis. Old Goatsas Navy alumni are calledwill complain that Plebe Summer has gotten too soft, but these youngsters are bright and eager and look as if they can take a lot of conditioning. The purpose of Plebe Summer, we are always told, is to build them up, not to tear them down. And always, its designed to build what military types call unit cohesion. During World War II, they called the group formed by that kind of camaraderie a band of brothers.

They look so young, my wife often says. They are. Most are just eighteen. Some are even seventeen. You can qualify for the Naval Academy up to but not after your twenty-third birthday. We know one family where the older brother, already a college sophomore, attended his younger brothers induction, and promptly decided he wanted to transfer to the Naval Academy. He had to start his college career all over againand salute the little brother who now outranked him!

The most moving moment of I-Day, the reason it is called Induction Day, is when the 1200 new Midshipmen take the Oath. Led by the Academys gold braided Superintendent, often with their tearful parents looking on, these young people raise their right hands and pledge to defend the Constitution of the United States against all enemies, foreign and domestic.

Its a joyous occasion. Some of the parents, doubtless, mix their pride with relief: Their son or daughter will have an excellent four-year education and graduate not only with a guaranteed job, but with no debt. Naval Academy Midshipmen not only pay no tuition, they actually receive a modest ($558.04 per month) salary while they are in school.

No one is morbid about it, but there is an undertone of solemnity in this important first step in a Navy or Marine Corps career. At least one of the Midshipmen whose induction my wife and I witnessed over the past thirteen years has his name inscribed in Memorial Hall. Marine First Lieutenant J.P. Blecksmith was killed in Fallujah, Iraq in 2003. Our daughter Elizabeth used to drive him around the town after a football injury required a knee operation. All give some. Some give all.

Kate and I join dozens of others from the Chapel to welcome unaccompanied Plebes. These are Midshipmen whose folks will wait until Plebe Parents Weekend in August to make the long trip to Annapolis. We invite Plebes to attend our Chapel services.

We give our Plebes juice and cookies, we chat with them, and let them use our cell phones to call their families. No one we saw in the Class of 2013 seemed near tears. The cooler weather may have contributed to this. They were cheerful, even jaunty.

As we leave Tecumseh Court, the large, open square where the induction ceremony has taken place, I can see that Kate is about to remark again how young they all look.

How young and how few. During World War II, with a military draft, one in every eleven Americans was in uniform. Today, with our all-volunteer military, only one in two hundred Americans defend our lives and liberties in a hostile world. I point to a group of folks standing under the trees. Look, Kate, its the parents of the Plebes. Dont they look young?