Correct me if I'm wrong, but I don't think that there has ever been a nation-wide declaration of marshal law in the USA-even during the Civil War. There was the suspension of certain rights and liberties during the Civil War (like habeus corpus, etc.) but no general marshal law.
I have gotten a chuckle out of some of the previous posts above-people with an obvious political viewpoint to forward making up historical "facts" to validate their viewpoints-like the FDR/WWII nonesense.
The first national income tax was instituted in the Civil War, and was declared unconstitutional. In 1913 the 16th Amendment to the Constitution was ratified permitting a federal income tax.
As to exactly when the Internal Revenue Service started, I do not know. As I recall, initially another institution/agency performed this function, but I could be wrong.
If you're really interested, I suggest researching the issue yourself-at the library (gasp) or through a search engine.