Political correctness may no longer permit kids to play cowboys and Indians these days, but it has not prevented the South Park kids from playing Texans and Mexicans. In an episode due to air tonight (Tuesday), Cartman leads a contingent of Texas rangers on border patrol behind a fence that is decked out with plastic forks taped to the top. On the other side of the fence is Butters, leading a group of grimy-faced Mexicans. A press release issued by Comedy Central,, which airs South Park , says that "Butters is filled with pride." However, it adds, "Not surprisingly, Cartman turns out to be really good at stopping Mexicans." The episode, titled "The Last of the Meheecans," is likely to embroil South Park creators Trey Parker and Matt Stone in yet another fiery controversy -- something that the pair haven't experienced in years. But the increasingly divisive issues of immigration and border security are stirring up ever angrier debate, especially among the Republican presidential candidates, and the episode seems certain to rile staunch supporters of a heightened crackdown on illegal immigration.