Minorities? For sure, if you're talking mainly about blacks and Hispanics.
But all immigrants? What about those non-black, non-Hispanic immigrants like the very prosperous Koreans and Chinese and Hindus that I see driving Mercedes and BMW's all around FFX? I don't claim to have poll numbers on how they will vote. What hard data do you have?
Immigration, Political Realignment, and the Demise of Republican Political Prospects
If you want to see how immigration impacts electoral politics, look no further than CA, which has the demographic profile today that the US will have in 2050. We are well on our way to the Dems being the permanent majority.
Immigrants account for one in 8 U.S. residents, the highest level in more than 90 years. In 1970 it was one in 21; in 1980 it was one in 16; and in 1990 it was one in 13. In a decade, it will be one in 7, the highest it has been in our history. And by 2050, one in 5 residents of the U.S. will be foreign-born.