Some will recall the strong view Lee shared in a letter written January 23, 1861 to his son Custis:
As an American citizen, I take great pride in my country, her prosperity and her institutions, and would defend any State if her rights were invaded. But I can anticipate no greater calamity for the country than the dissolution of the Union. It would be an accumulation of all the evils we complain of, and I am willing to sacrifice everything but honor for its preservation. I hope, therefore, that all constitutional means will be exhausted before there is a resort to force. Secession is nothing but revolution. The framers of our Constitution never exhausted so much labor, wisdom, and forbearance in its formation, and surrounded it with so many guards and securities, if it were intended to be broken by every member of the Confederacy at will. It is intended for perpetual union, so expressed in the preamble, and for the establishment of a government (not a compact) which can only be dissolved by revolution, or by the consent of all the people in convention assembled. It is idle to talk of secession. Anarchy would have been established, and not a government, by Washington, Hamilton, Jefferson, Madison, and the other patriots of the Revolution.
<J. William Jones,
Life and Letters of Robert Edward Lee, Soldier and Man. (New York: Neale Publishing Company, 1906), pp. 120-121.>
Lee in January 1861 saw secession as a catastrophe, a "revolution" that he clearly opposed.
After 1865, Lee argued that secession was not only legal, but right.
Edited.