Lots of anti-immigration people claim that they oppose having large numbers of foreigners enter the USA because such migrants are, in effect, nothing but future Democratic voters, and anything that strengthens Democrats in the political process is bad for the country in general. In a way that is true. But it would be equally true if the migrants portended a strengthening of Republicans in the political process. Both major parties advance an evil program; they simply go about it in somewhat different ways.
The fundamental problem is not having more Democratic voters or more Republican voters, but the fact that so many things are being decided in the political process that ought not be up for a vote in the first place. So long as both parties support, in general, unlimited government, it makes little difference which party packs the greater punch. Each party is doing everything it can to lead the country to ruin. All the rest is smoke, mirrors, and bullshit.