i dont' think it would damage too much, it would simply increase the workforce of america opening a wider variety of jobs, help currency to stay in the country, return immigrants to their native countries(within reason of course) and then spend more time on america...but i don't think any countries will want to sever relations with america, we may be hated but when people need a hand...it's america they turn too...

but america is becoming a rather powerfule "rome" it's just sad that the comparison is so easy to make remebering what happened to the romans...