Notwithstanding current law & this and prior administrations' lack of enforcement, the 'purest' conservative solution is the open market. Illegal immigration has grown in proportion to our 5 year economic expansion, and will deflate in the face of the next recession.
Our opportunity is merely to enforce existing laws regarding identification & employment and pursue lawbreakers to facilitate normal market mechanisms. Already, we're beginning to see reports of businesses losing entire work forces under the first whispers of crackdowns. This will only accelerate as unemployment numbers creep up in the next recession.
The key is enforcement of employment ID laws & self-deportation. We don't need to stinkin' fence or amnesty.
In a normal time I would agree that we don't need a fence if we actually punished lawbreaking employers etc. However we have more than job seeking Mexicans crossing our borders. We know that terrorists have crossed both borders. Also we have Hugo Chavez snuggling up to the worst terrorists around.