The phrase hireling and slave in the anthem refers to British soldiers and mercenaries rather than African-American slaves.

“I would have said that these are insults applied to soldiers fighting under the British Crown.”

The anthem contains ambiguous lyrics that might be interpreted as a glorification of slavery given Key's history as a slave owner and opponent of abolition.

“I think it is perfectly possible he is talking about these people whose flight has been such a big story. He is saying, basically, we will catch up with you or you will die.”