Yep, just tell them the truth. Once the public is educated about just how many crimes are being committed by the illegal invaders, the M-13 gangs, drug smuggling over the border, in how much it costs us to capture, try, and incarcerate them, how much they cost us in insurance rises due to their driving w/o insurance, how much they cost us in free medical benefits, welfare benefits and college tuition reductions, and tax evasion, then convincing the American public to boot them out will be easy. The money we are saving on cheaper lettuce and tomatos is paltry compared to what it costs us to host these 20 million misfits from south of the border. Politicians hate the truth.
Read my tagline (but if the Senator McCain proposal were implemented it would be almost 25 cents more)