I have heard this story multiple times over many years. But I’ve never been able to verify it to my satisfaction. I’ve been told that knowing the Star-Spangled Banner lyrics beyond the first verse could get one killed.
This is, specifically, a World War II tale. When a presumed fellow American soldier came through the terrain, the guards wanted to know if they were truly Yanks as claimed. If they knew the latter verses of the national anthem, they would be summarily shot. The theory was that NO one knows those except a spy feigning to be from the USA.
Good thing I wasn’t there because I would be dead. In fact, in our elementary school, Daniel S. Dickinson, our music teacher had us singing a panoply of patriotic songs, such as Columbia, The Gem Of The Ocean. Plus the standard fare: America, America The Beautiful, Yankee Doodle, and The Battle Hymn Of The Republic.
So I know the second and fourth verses. Yeah, that last one IS rather Manifest Destiny. “Then conquer we must, when our cause it is just, And this be our motto – ‘In God is our trust.'”
The hireling and slave?
But to the best of my recollection, our songbook did not include that third verse, so I didn’t know it, though I was aware of its existence:
And where is that band who so vauntingly swore,
That the havoc of war and the battle’s confusion
A home and a Country should leave us no more?
Their blood has wash’d out their foul footstep’s pollution.
No refuge could save the hireling and slave
From the terror of flight or the gloom of the grave,
And the star-spangled banner in triumph doth wave
O’er the land of the free and the home of the brave.
What the heck does THAT all mean? A conversation in the Washington Post may enlighten.
Scorn
“These lyrics are a clear reference to the Colonial Marines, according to Jefferson Morley, author of ‘Snow-Storm in August: Washington City, Francis Scott Key, and the Forgotten Race Riot of 1835.’ They are clearly meant to scorn and threaten the African Americans who took the British up on their offer, he wrote in a recent essay for The Washington Post. Key surely knew about the Colonial Marines, and it’s even possible he saw them among the contingent of British ships that sailed into Baltimore Harbor.
“But Mark Clague, a musicologist at the University of Michigan and an expert on the anthem, disagrees. In 2016, he told the New York Times: ‘The reference to slaves is about the use, and in some sense the manipulation, of Black Americans to fight for the British, with the promise of freedom.’ He also noted that Black people fought on the American side of the war as well.
“Whether manipulation or not, the British kept their word to Colonial Marines after the war, refusing the United States’ demand that they be returned and providing them land in Trinidad and Tobago to resettle with their families. Their descendants, called ‘Merikins,’ still live there today.”
FSK
As for the writer of the poem, “And even if these lyrics aren’t meant to be explicitly racist, Key clearly was. He descended from a wealthy plantation family and enslaved people. He spoke of Black people as ‘a distinct and inferior race’ and supported emancipating the enslaved only if they were immediately shipped to Africa, according to Morley.”
Oh, it gets worse. “During the Andrew Jackson administration, Key served as the district attorney for Washington, D.C., where he spent much of his time shoring up enslavers’ power. He strictly enforced slave laws and prosecuted abolitionists who passed out pamphlets mocking his jurisdiction as the ‘land of the free, home of the oppressed.’
“He also influenced Jackson to appoint his brother-in-law chief justice of the United States. You may have heard of him; Roger B. Taney is infamous for writing the Dred Scott decision [1857] that decreed Black people “had no rights which the White man was bound to respect.'”
Confederate victory
It’s interesting that Key’s “overt racism” prevented the famous song from becoming the national anthem during Key’s lifetime. There was no official anthem. People sang various other songs such as the ones I referenced earlier.
“Key’s anthem gained popularity over time, particularly among post-Reconstruction White Southerners and the military…
After the misery of World War I, the lyrics were again controversial for their violence. But groups like the United Daughters of the Confederacy fought back, pushing for the song to be made the official national anthem. In 1931, President Herbert Hoover made it so.
“‘The elevation of the banner from popular song to official national anthem was a neo-Confederate political victory, and it was celebrated as such,’ Morley wrote. ‘When supporters threw a victory parade in Baltimore in June 1931, the march was led by a color guard hoisting the Confederate flag.'”
Civil War reply
A little-known, unofficial fifth verse was written a half-century later by poet Oliver Wendell Holmes, clearly a response to the American Civil War. It was new to me.
When our land is illum’d with Liberty’s smile,
If a foe from within strike a blow at her glory,
Down, down, with the traitor that dares to defile
The flag of her stars and the page of her story!
By the millions unchain’d who our birthright have gained
We will keep her bright blazon forever unstained!
And the Star-Spangled Banner in triumph shall wave
While the land of the free is the home of the brave.
Walking home from the store back on March 31, I wondered why the flag nearish the police station was at half-staff. 
There is an article in 
