I read a very interesting post on the Yglesias blog concerning conservative's views concerning immigration. The post quoted an article written by Ron Call, which essentially pointed out a "split" in the views of conservatives regarding immigration. On the one side, there are the conservatives against immigration at any cost, even likening illegal immigration to "an invasion." However, there is also the school of thought that conservatives should maybe favor a more "liberal" solution for illegal immigration, and pursue policies that would make it easier for immigrants to become part of American society. One of the only things keeping many Latino immigrants from voting with the Republican party is its stance on immigration. "Latinos actually share values that are staples of conservative campaigns...[t]hey're overwhelmingly Christian, pro-business, and oppose gay marriage and abortion rights." If the Republican party were to become more "pro-immigration," they could gain a very large (and rapidly growing) constituency.
Personally, I do not think that the Republican party will adopt a more flexible stance on immigration anytime soon. Honestly, there are too many Republicans in the immigrants=invasion boat. But if they were to do so, I think it would cause a considerable voter shift.