The U.S. political system would have to be completely overhauled in order for one person to make a difference. Especially as President. If someone actually did a study on the mechanics of our 3 branches of government and the usefulness of them, I'd guess every positive change is matched by at least 10 parts obvious corruption, and who knows how much unadvertised corruption.
I don't want Lessig to waste his time in that clusterfuck because I think he's too good of a guy and doing too much good from an outside perspective. I think the best thing for the Republicans is that the Dems make him the president - and absolutely nothing would get done for 4 years, at least until there was an anti-American impeachment hearing. The only thing he might have direct influence over *might* be Executive Directives, and they'd get put right back in after they shoved him out (if anyone ever stopped following the current ones).
In "The Day the Earth Stood Still" (2008) Jennifer Connelly's character said (approx): "Leaders? [The President and the UN] aren't our leaders - I'll take you to one" and she takes him to a Nobel Prize winner in "cooperative biology" - a brilliant, thoughtful person.
Lessig is more than just a thoughtful person, and rather than seeing him get beat down by the political system - ESPECIALLY if he were to win the Presidency! - I hope he continues making more and more of a difference as a professor, private citizen, and activist.
Best of everything to you, sir!