I worked in manufacturing for 7 years during the last decade, and my dad was an advisor to the congressional panel with Nafta. I can tell you exactly why the economy took it's downfall, and why it can't recover, and why China will overtake us as the world's #1 superpower.
When Nafta was signed, there were provisions (there was also a deal made with central america that escapes my mind at the moment). Most of the parts makers and fabric makers stayed in the US, and they used cotton grown in the US. I have signed pictures of Clinton signing the bill, which I have since destroyed. But a perspective from someone that was working in central america and watching the battle that was being waged during the late 90's through to about 2006 when the problems really started, this is how it went.
Clinton signed Nafta and actually brought a lot of jobs back to the US. Cotton farming grew and the textile mills were all running heavily. Cars were being made primarily in the US and most of the outsourcing was to Mexico. During this time no one really was paying attention to the illegal immigration because it was just taking the jobs no one else wanted. Clinton also signed a bill during his 2nd term that limited the amount of certain goods (textiles ect) that could be imported, and there was a heavy tariff to the tone of 17-27%. This bill was slated to last 10 years.
Fast forward 9 years. The bill is running out, and many companies in the textile industry (I'm most familiar with this so I'll stick to this) began selling off their manufacturing arms and becoming only marketing agencies. Almost every major brand did this. They turned to "full package development" instead of designing their own, where a company brings them a final product and a price and the company says yes throw our label on it or no we don't like that. This is also true of electronics, I have an mp3 player made by a company that sells the same exact one to 3 different brands.
During this time a record number of gigantic new cargo ships were constructed. China had been running full capacity and selling all their old stuff to us for 10 years and had so much product in storage they were just waiting out the clock. Bush, in one of the only things he did during his 2nd term that was worth a damn, tried to pass an ordinance that would extend the tariffs. Unfortunately the Democratic congress didn't want to basically change a bill that a Democrat president had put into service.
The final straw was when the levee broke, and the flood of chinese goods hit the market. I was still in central america at this time, and saw 100's of thousands of jobs go away, because we had to use 80% American cotton to avoid a 30% tariff when the chinese were just using chinese cotton, or middle eastern. Now you take a country like Honduras, that 15 years before had been just an awful place to live, shanty towns, poor sewage systems, basically 3rd world at it's apex, and you throw American money into it for 15 years. People start having larger families, building malls, McDonald's ect opens up, jobs are plentiful, then all the sudden 15 years down the line BAM everyone pulls out. Around 2005-2007 is when the whole illegal alien movement started getting people's attention. Obama in his election speeches talked about amnesty for illegals. The newspapers all over central america were saying that anyone in the US when Obama is elected if he wins will get legal status.
Illegal immigration booms. And at the time the economy was only at the start of it's downfall. I said at the time it didn't matter who got elected, that Obama would just make the downfall faster. Bush, being completely inept and having his hands tied, pretty much just sat there unable to do anything, probably getting coked up.
So now we have record unemployment, up to an estimated 5-10% of the residents of the US are illegal, and no one is buying American, unless you buy a Mazda or a Toyota, since japanese car companies are still producing cars here. American car companies have gone elsewhere. The recent uproar in Honduras a few years back with the president being thrown out by trying to sneak an illegal vote on a bill through, and similar governmental problems in Nicaragua and the Dominican Republic are just telling the residents that they are better off risking their lives to cross the border.
Anyway, wall of text over. This is just one of the major factors that no one tells you about when they are pointing fingers, because both parties fucked it up.