"The despot's heel is on thy shore" DID refer to Lincoln. The State had been invaded.
The line "Avenge the patriotic gore/that flecked the streets of Baltimore"
Referred to the first fatalities of the war, in the 1861 street riots where Baltimore citizens attacked invading troops.
People forget that a person's primary loyalty was to their State, not the managers of the Federal District.
Either STFU, Liberals, or just burn the >bleep< books and get this over with!