in history. During times of severe crisis or war nationalism pulled a country together enabling them to overcome from being pounded flat. It can keep a country strong and together for long periods as well. The Roman Republic and Empire lasted about 1000 years. It was highly nationalistic as well as expansionist leading to Pax Romana (Roman Peace) for over 200 years during its period of greatest expansion. It brought Roman law and culture to the far reaches of the Empire, Romanizing the various conquered peoples and kept the Empire free of any major social disorder or conflict. The Empire in fact declined when its nationalism and the civic duty it inspires declined.
During WW2 Americas nationalism helped us win the war. We could not have won WW2 without our nationalist attitude. Most of the Japanese high command (The Nazis too)thought the US was weak and would not fight if it could be avoided and underestimated our industrial capacity and resolve. Admiral Yamamoto the mastermind of Pearl Harbor stated "I am afraid we have awakened a sleeping giant" after the attack. Yamamoto was against attacking the US because he had lived in the US for many years and knew our industrial might and our capacity to pull together would grind them down, but as a military man he followed orders. He believed Japans only hope (even this was a long shot)was to attack Pearl Harbor and knock out our carriers and a good part of our Pacific fleet crippling our ability to attack for years. Then force us to make a peace agreement.
Yamamoto was right because after the attack we pulled together with a singular nationalist resolve to pound Japan and Germany to dust. The Arsenal of Democracy,s industrial might kicked into high gear out producing everyone else put together. Nationalism made our victory in WW2 possible.
Here are some of our nationalist posters in WW2 some are pretty extreme





During the Civil War the US did not get pounded flat, our industry went into high gear and pounded the South to their knees. The North was pretty much intact while the South was completely devastated. It was the first modern type of warfare using the principle of total war which was used by Sherman so devastatingly on the South. Slavery tore the union apart and nationalism saved the union.
Nationalism can be good or bad and does not necessarily end up with the country getting pounded flat. On the contrary it can save the country from such a fate and can even push a country to make great advances such as putting a man on the moon. Nationalism when coupled with xenophobia on the other hand is when nationalism can turn ugly.
Some nationalist quotes
"These are the times that try men�s souls. The summer soldier and the sunshine patriot will, in this crisis, shrink from the service of their country; but he that stands it now, deserves the love and thanks of man and woman. Tyranny like hell is not easily conquered yet we have this consolation with us, the harder the conflict, the more glorious the triumph. What we obtain too cheap, we esteem too lightly; it is dearness only that gives everything its value." -- Tom Paine after the Declaration of Independence
"Our citizenship in the United States is our national character. Our citizenship in any particular state is only our local distinction. By the latter we are known at home, by the former to the world. Our great title is AMERICANS�" -- Thomas Paine
"I only regret that I have but one life to lose for my country." -- Nathan Hale's last words before being hanged by British.
"What kind of a people do they (Japan) think we are? Is it possible they do not realize that we shall never cease to persevere against them until they have been taught a lesson which they and the world will never forget?" -- Winston Churchill
"We shall defend our island whatever the cost may be; we shall fight on beaches, landing grounds, in fields, in streets and on the hills. We shall never surrender and even if, which I do not for the moment believe, this island or a large part of it were subjugated and starving, then our empire beyond the seas, armed and guarded by the British Fleet, will carry on the struggle until in God's good time the New World with all its power and might, sets forth to the liberation and rescue of the Old." -- Winston Churchill
"We have before us an ordeal of the most grievous kind. You ask, what is our policy? I say it is to wage war by land, sea and air--war with all our might and with all the strength God has given us--and to wage war against a monstrous tyranny never surpassed in the dark and lamentable catalogue of human crime. That is our policy." -- Winston Churchill
"Let every nation know, whether it wishes us well or ill, that we shall pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and the success of liberty." -- John F. Kennedy
"(W)e here highly resolve that these dead shall not have died in vain; that this nation shall have a new birth of freedom; and that this government of the people, by the people, for the people, shall not perish from the earth." -- Abe Lincoln in the Gettysburg Address
"Four score and seven years ago our fathers brought forth on this continent, a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal." -- Abe Lincoln in the Gettysburg Address
"A house divided against itself cannot stand. I believe this government cannot endure permanently half-slave and half-free. I do not expect the Union to be dissolved - I do not expect the house to fall - but I do expect it will cease to be divided. It will become all one thing or all the other." -- Abe Lincoln