[hang 'em]

1) Mine the borders.

2) Put cash bounties on illegal aliens (i.e. a citizen gets say $100 for ratting out an illegal)

3) Bounties on businesses that hire illegals.

Problem solved.

[rightofrush]

1) Mine the borders.
2) Put cash bounties on illegal aliens (i.e. a citizen gets say $100 for ratting out an illegal)
3) Bounties on businesses that hire illegals.
4) Machine gun towers and use the current technology of survailance drones.

Now the problem is solved.