[DiogenesLamp]

The truth is that Maryland refused to secede, remaining a "Union state and that made all Maryland pro-Confederates treasonous. The claim that Lincoln waged war against Maryland is just cockamamie nonsense, worthy of Democrats like crazy Roger Taney."

The despot's heel is on thy shore,
Maryland!
His torch is at thy temple door,
Maryland!
Avenge the patriotic gore
That flecked the streets of Baltimore,
And be the battle queen of yore,
Maryland! My Maryland!

Dear Mother! burst the tyrant's chain, Maryland!
Virginia should not call in vain,
Maryland!
She meets her sisters on the plain-
"Sic semper!" 'tis the proud refrain
That baffles minions back again,
Maryland!
Arise in majesty again,
Maryland! My Maryland!

I hear the distant thunder-hum,
Maryland!
The Old Line's bugle, fife, and drum,
Maryland!
She is not dead, nor deaf, nor dumb-
Huzza! she spurns the Northern scum!
She breathes! she burns! she'll come! she'll come!
Maryland! My Maryland!

https://msa.maryland.gov/msa/mdmanual/01glance/html/symbols/lyricsco.html

[BroJoeK]

DiogenesLamp quoting Maryland's song:

"The despot's heel is on thy shore, Maryland!
His torch is at thy temple door, Maryland!
Avenge the patriotic gore
That flecked the streets of Baltimore,
And be the battle queen of yore,
Maryland! My Maryland! "

The fact is that Maryland's legislature voted four-to-one against secession in April 1861.
After Confederates declared war against the United States, only one-third of Maryland's legislators were considered pro-Confederate traitors.
Marylanders served in the Union Army about two-to-one over the Confederate army.

So Maryland was a Union state by law and by its citizens' sympathies.
That makes those who supported the Confederate cause traitors to the United States, regardless of their later propaganda prowess.