What happened to unity an patriotism?

Until Nancy Pelosi came along, it was understood by all that we had only one president at a time and -- like him or not -- he alone had the Constitutional authority to speak for this country to foreign nations, especially in wartime.
All that Pelosi's trip can accomplish is to advertise American disunity to a terrorist-sponsoring nation in the Middle East while we are in a war there. That in turn can only embolden the Syrians to exploit the lack of unified resolve in Washington by stepping up their efforts to destabilize Iraq and the Middle East in general.
Members of the opposition party, whichever party that might be at a given time, knew that their role was not to intervene abroad themselves to undermine this country's foreign policy, however much they might criticize it at home.
During the Second World War, the defeated Republican presidential candidate, Wendell Wilkie, even acted as President Roosevelt's personal envoy to British Prime Minister Churchill. He understood that we were all in this together, however we might disagree among ourselves about the best course to follow.
Today, Nancy Pelosi and the Congressional Democrats are stepping in to carry out their own foreign policy and even their own military policy on troop deployment -- all the while denying that they are intruding on the president's authority.