You are aware that what you are talking about occurred in September 1861? Months after the Civil War had begun? And that would mean that the Maryland legislators that you spoke of, who were a minority to begin with, were advocating joining a war ongoing against the federal government? Given all that then what would expect the government to do?
Congressman May was arrested in May of 1861 by General Butler when he declared marshal law in Baltimore. The Maryland legislatures were arrested in September of that year..