Debt Ceiling

In October of this year Congress will be forced to raise the National Debt Ceiling yet again. This raise will be on 1.8 Trillion Dollars. There has been a history of this kind of behavior since a national debt limit was created. Already it has been raised twice this year, leaving it currently, at 13 trillion. They say that if Congress does not raise the debt ceiling that the nation could be forced to default. But would that really happen? What would the result of America going bankrupt be? Because the economy is no longer specific to each country, I think that that would greatly hurt the global economy. But, even though, I doubt this is in our future, what would a nation going bankrupt look like. Would we be taken over by China? Our government falling apart and our country being split up and sold like a business?
Another question I have, is what is the point of a National Debt Ceiling, it looks to me like it hasn't had much effect on national spending. There was a bill created to try to minimize government expenditure, but it has had little effect. So is there a point to a ceiling that is moved every time we have a crisis? That doesn't seem like much of a control at all. The government is like a small child, it knows its parents will give in, even if they say no at first, if they push and cry enough. If rules arn't enforced, they are more damaging then good.