If he made it to all of the states individually, then he violated it whenever he operated outside of Virginia. The same cannot be said of Union officers following legal orders of the United States to suppress rebellion in some of the states.I dont think you get the point I am making. I admit its a bit legalistic, but then I am a lawyer. Since the oath used the plural to refer to the US, its as if Lee made an oath to each and every state. So how could he comply with his oath if he defended some states, and fought against others? So in a sense, Grant violated his oath when he fought against Virginia, since he swore to defend Virginia against all of its oppressors.
And I did not say secession was legal. I said the legislature voting to secede was a legally permissible act. There was no precedent at that time that said secession was illegal. If you know of any cases on that I would be interested in reading them. It was not until the Supreme Court determined in Texas v. White in 1868 determined that secession was legal. So until the Constitutional question was finally determined one way or another, State legislatures are free to legislate. But after their is a definitive ruling, then sates no longer can legally legislate in areas of settled law. Secession was simply an unsettled question in 1860.
Whether he resigned or not is irrelevant to my legal reasoning.
And I do not think Confederate traitors are heroes. I am no lost causer by any means.