I'm currently in Boston for a couple of days. In recent visits to the US, I've noticed a worrying trend. When you enter the border, you're bombarded with tight security requirements. They want your photo, your thumb print, as well as the opportunity to interrogate you on why on earth you are trying to enter their country.
Of course all these steps are perfectly acceptable and legitimate for any country, especially one that has faced terrorist attacks in recent years... although you wouldn't know that this were the reason from the official explanation for the tighter security. I listened with half an ear to the Homeland Security video played on the Cathay Pacific flight as we came in to land, which tried to sell these changes as increasing the efficiency of travel.... which it clearly does not! I guess a sales pitch of "we're going to take a close look at you because if you're a terrorist, we want to make your life hell! Otherwise, we hope you'll put up with the inconvenience. And have a nice day" might not appeal to all, but at least it would be honest. And when a government doesn't come clean about the real reasons for their actions, it leaves plenty of room for us to wonder what "big brother" is really up to.
More importantly, I fear that the changes are part of a more disturbing trend. Since 9/11, America has become more paranoid and less trusting of the rest of the world. Of course this is a two-way street... the Iraq debacle has left the rest of the world more paranoid and less trusting of America. However, I fear that this may start to have an increasing effect on the world economy. Not only are American's increasingly paranoid about people entering at the border, but they're paranoid about capital flows (remember when China tried to buy an American oil company?), free trade (loss of low skilled jobs to Asia), Russia, and most of all China. In a democracy, that will likely lead to a less open economy in future.
Openness is a sure driver of economic growth. It allows skilled migrants to move where their skills are most valued, ensuring maximum social return on their human capital; economies to specialise in producing the goods and services for which they have a comparative advantage, ensuring efficient resource usage; rapid technology diffusion, allowing poor countries to catch up more quickly to rich countries; and reduced levels of corruption, since corruption is essentially a tax on domestic firms, and puts them at a disadvantage relative to foreign competitors.
Paranoia, on the other hand, will lead to reduced efficieny and reduced growth. In the end, both America and the world economy will suffer the consequences.