We in the U.S. military are privileged to defend America, especially at this time of year, for we ensure our fellow Americans celebrate this season of hope in peace and safety.We know our freedoms are not guaranteed by themselves; they need defenders.This month, many in our military will be serving far from their loved ones. It is difficult work, but this is nothing new: Since [George] Washington crossed the Delaware on Christmas Day in 1776, American Troops have missed holidays to defend our citizens' experiment in democracy.To those in the field or at sea, "keeping watch by night" this holiday season, you should recognize that you carry on the proud legacy of those who stood the watch in decades past. In this world awash in change, you hold the line.Storm clouds loom, yet because of you your fellow citizens live safe at home. Most don't know your names but all are confident their freedoms are their families will be kept safe.Far from home, you have earned the gratitude and respect of your fellow citizens and it remains my great privilege to serve alongside you.Merry Christmas and may God hold you safe.-- U.S. Secretary of Defense, James N. Mattis