But by allowing in more Mexicans, they may be raising the number of Mexican Americans voting Dem even more. Open borders is bad policy and very possibly (for the GOP) bad politics.
On the surface your premise seems to make sense...
Apparently though, the GOP is betting on a different model that somehow creates a voter trend in their favor -- regardless of any negative ramifications the sanctioned flooding of legal/illegal Third World immigration produces.
IOW -- American sovereignty is being sold out for what else? POWER.