At my husband's former job a few years ago, a Mexican co-worker boasted to him that the LATINOS were taking over. He was really proud of this fact. My husband calmly said to him, "well who's going to pay all the welfare when that happens". He was mad but it shut him up.
Noone is "taking over." Americans are giving it up. They couldn't take back their own country so they came here knowing what pushovers some Americans are.
I love it. I might use this tactic at one place I occasionally work at, where this might come up.
And I'll say it with a big smile too. :o)