Of all patriotic holidays, Memorial Day is the one that has the most immediate impact and is kept most current in the minds of Americans. This is not a day to honor a long-dead political leader or to commemorate the end of a war or the founding of the nation. It is a day set aside to honor those who have paid the ultimate sacrifice to preserve the liberty the rest of us freely enjoy.

And that sacrifice, never to be taken lightly, is constantly required as each generation faces new challenges.

Only a few days ago, Command Sgt. Maj. Martin R. Barreras from Tucson, Arizona, died when his unit came under fire in Afghanistan, according to the Associated Press. The United States is quickly reducing its force level in that country as the Afghan people take control of their own government and security, and yet American soldiers continue to put their lives on the line there every day, as they do elsewhere in the world.

Only a few days after Barreras’ death, Spec. Adrian M. Perkins of Pine Valley, California, died in Amman, Jordan, from injuries suffered in a non-combat situation, the AP said. Just 19 years old, he, too, is a hero who willingly put his country ahead of his own hopes and dreams.

So far in 2014, 21 U.S. casualties have been recorded around the world, according to the website icasualties.org.

Unlike so many other world powers in history, the United States sends its forces abroad to preserve an idea, not to expand its power. In Afghanistan, people now have an opportunity to grasp freedom through a representative government. Tyranny, for the moment, has been set aside. America’s service men and women truly sacrifice for a noble cause.

Few causes were as noble as in World War II, when the condition of freedom worldwide was dire. Today, the Veterans Administration reports that about 555 World War II vets are dying each day — a figure that is slowly shrinking as the number of such veterans dwindles. Only about 1 million of them remain, with 8,097 in Utah.

The consequences of their service, offered without complaint and with no sense of entitlement, will last far longer than their lives. The nation’s debt of gratitude toward them can be repaid only through our own devotion to preserving freedom and liberty.

Throughout history, Americans have shown they value freedom-keeping more than peacekeeping. Together with freedom-loving allies, they have made the world a place where ambitions, hopes and innovation have a lasting foothold.

The vast majority of Americans will celebrate the beginning of the summer season today with parties and barbecues. It is appropriate to do so, but it also is appropriate to remember those who make such carefree celebrations possible. We need to make sure that the rising generation understands the tremendous cost that continually is required.