Lines 1-4:

The first stanza meditates on the ship's "ensign," or the naval flag that flies upon its mast, as a symbol of the Constitution herself. Though not invented by Holmes, "Old Ironsides" is a metaphorical nickname—ironclad vessels did not come into use until the Civil War—and like the "tattered" flag, the ship has survived much adversity. Also like the flag ("Long has it waved on high"), the ship occupies a lofty position—not physically, of course, but in the imagination. Because of its role in history, the Constitution is in the national consciousness a symbol for the "higher" virtues for which the republic is thought to stand. One such virtue is freedom, and in the early days of the United States the concept of freedom was closely associated with the two wars against Britain. Thus the ship is an important symbol to the many Americans...