Where are we now, three years into the War on Terror?
Three years into the American Revolution, the war was not yet half over.
Three years into the Civil War, the Union was executing a massive campaign against the South involving all of the Union armies. Lee surrendered to Grant a year later.
America's involvement in World War 1 lasted only for fifteen months.
Three years into America's involvement in World War 2, we were fighting the Battle of the Bulge, Hitler's last desperate offensive. Paris had been liberated four months earlier.
Three years into America's involvement in Vietnam, we were in the thick of battle and the war would last another nine years.