SPOKANE -

It's the ultimate form of respect; flying a flag at half-staff to honor a soldier killed in action. This Independence Day weekend, we look deeper into that time-honored tradition to find the real meaning. What does it really mean to fly a flag at half-staff? Where does this tradition come from?

The gesture itself could not be more simple; the powerful symbol of our nation's freedom, genuflecting. Half-staff, but whole-hearted to honor and remember.

"It's done to show respect to those who have given the ultimate sacrifice," says Capt. Clayton Colliton, a military history professor at Gonzaga University.

Last week, the flag was at half-staff to honor Joshua Robert Dumaw; a son, a brother, a soon-to-be father, a friend and a Marine, killed in action in Afghanistan. Dumaw's father calls him a "Marine's Marine" and the most brave man he's ever known. His death proves that behind every half-staff flag is a man or woman who laid down their life for our country. How many have their been? Countless, since the tradition began centuries ago.

"There's two schools of thought," says Capt. Colliton. The first, he explains, comes from Naval tradition. "The concept was, after a Naval battle, all the riggings with having to move the ropes up and down, sometimes the flags would fall. So, out of respect for the battle, they would leave those masts and leave the flags flying at half-mast."

The other school of thought is that Armies would dip their colors to show respect to their superiors. And, there's an even older legend. In European mythology, fleets that lost a sailor would leave a space for the "ghost flag" to fly above the nation's colors.

As far back as the death of Abraham Lincoln, the flag was lowered to mark his passing. It's an invisible symbol of a tangible loss, with strict protol for how it's raised and lowered.

"You have to raise the flag all the way to the top, then lower it to half," says Capt. Colliton.

In Washington, Governor Gregoire orders the flags lowered for every service member killed in action. Last week, the nation's flags were lowered to mark the passing of Senator Robert Byrd. Next week, it could be someone else; another flag, another chance to remember how much is given for our freedom. Next week, it could be someone else's son.