Patriotism is national self esteem. Without patriotism, there is no sense of identity and pride, there can be no extension of the national competence and strength. Social collapse then is inevitable.
Patriotism begins as a noble virtue, pride in one's nation, devotion to its welfare and loyalty to its government. It ends as vulgar vice, its propaganda whipping up inhuman images of enemies and inciting war and the manipulation and exploitation of its non-rational elements lead to demagoguery. It is used to sanctify racism, sexism, anti-unionism, profits, witch hunts and bigotry. As Samuel Johnson said in 1775, "patriotism is the last refuge of a scoundrel".
Beware the leader who bangs the drums of war in order to whip the citizenry into a patriotic fervor, for patriotism is indeed a double-edged sword. It both emboldens the blood, just as it narrows the mind. And when the drums of war have reached a fever pitch and the blood boils with hate and the mind has closed, the leader will have no need in seizing the rights of the citizenry. Rather, the citizenry, infused with fear and blinded by patriotism, will offer up all of their rights unto the leader and gladly so. How do I know? For this is what I have done. And I am Caesar. (Julius Caesar).