Do we need a bonding factor?

I just finished watching Band of Brothers and was thinking about what makes Americans proud of their country. They dont have a history of 1000 yrs nor do they have a culture. America is a country of immigrants. British, Italians, Mexicans, Cubans, Indians...you name them and they are there. America is not even their native but they are overtly proud of it. There is unmistakbly a sense of bonding and brotherhood among Americans. With all the differences and without a cultural heritage to bind them, what else makes them bond together and be proud of their country?
And India with her history of over 2000 years and a culture that stands the test of time is not given due respects that she deserves from her people.
What is the reason behind these ironies in America and India?
Perhaps the cultural heritage and historical achievements are no longer a bonding factor for the present generation. So when i try to think of what could possibly be the bonding factor for the present generation, I'm not exactly sure of the answer. However, it makes me guess that a crisis of somekind influenced by an external entity, may be a war, could bind the people together. God forbid such a thing happens, but seeing America which goes for war once in 25 years, it compels me to think so. The present generation of India has never faced such a crisis and I feel we are taking too much for granted of our freedom. On the contrary, I see Americans having their flags in workspaces, in cars, in front of homes, in shopping malls etc. Not that I say displaying one's national flag alone is patriotism. I can never recount an instance where an American cribbed about something that is American, which is quite opposite of our Indian nature.
Patriotism is not just supporting India in sports. Its more than that. The feeling that it is our country, we made the laws and hence we should adhere to the laws, is what would be the minimum criterion for being patriotic. There should be compulasary military service for youngsters to achieve this kind of a feeling.
I sincerely hope I'm proved wrong and Indians are indeed patriotic without an external bonding factor like a war. Jai Hind.