The Catholic vote today is the same as it has always been in America, immigration from a more pure Catholic nation, founded as a Catholic nation by Catholics, hasn’t made any difference in it.
One cannot deliberately ignore history and Church teaching and expect to be taken seriously. Catholicism and Marxism are incompatible. Mexico has NOT been "a pure Catholic nation" for a long time now.
Here is an example of what marxist atheists did to Catholics in Mexico: