The early conversation here seems to focus more on US procedures and government branches than Twitter's responsibilities but Twitter is not just accessible to US world leaders. What would happen if some Middle Eastern monarch used the service to declare war on a neighboring country. I think even the UK still does war declaration from only the Queen, how should Twitter respond to it then?
How could an American company commit treason in a foreign country? Treason in a country you aren't a citizen of, in a country you have no moral, ethical or logical obligation to be loyal to, seems nonsensical. If country A invades country B, country A isn't committing treason against country B. Treason isn't just some word meant to describe "anything a country dislikes".