We will regret our reluctance to get a handle on illegal immigration. We are spending BILLIONS on homeland security, multi millions on beefing up security in NYC, DC and Newark right now, yet we invite the terrorists in on our southern flank. Of course, after the next major terrorist attack, it is determined that the perpetrators came into the US from Mexico(too late obviously), we'll begin to take this issue seriously. Unfortunately, our enemy will have already succeeded in getting all the terrorists into the country. I am so afraid this nation will live to regret(many won't though) not doing something sooner.
I'm not even sure that would have an effect. 20 percent of the illegals who cross the Mexican border are VIOLENT felons, and the violent crime they perpetrate is just as bad as any terrorist attack.