The recent spurt of mortgage defaults:

I would suggest that what Karl Rove was paying attention to wasn't just particular minority groups, but that hewas attempting to ingratiate the GOP with the political and business establishments in states that were likely to be key in national elections.

Even when immigration isn't directly affecting apportionment of electoral votes, there is an indirect effect, because much of the growth in other states relates to Americans leaving high immigration states like California. If you look at the direct effect of immigration, there has been a tendency to swing votes towards Democrats. However, the net effect of apportionment has been towards Republicans(i.e. a Democrat that won the same states as Gore in 2000 wouldn't be as close to the White House as Gore was). One of the oddities of the Electoral College  is that minor movements of population can have a significant impact on national elections. I can't help but wonder if part of Rove's logic in encouraging lending patterns was to create an electoral map that had some short term advantages for GOP candidates-and this whole plan backfired wildly.