The reasoned immigration chat won't happen until we start looking at what our "empty land" does, what it can and can't support, and what stresses of rapid population growth our social infrastructure can handle. Like Australia, our land area is deceptive in its size, suggesting a greater capacity than it has. Some of it is desert, and we're already stretching things having so many people living there (Get out of there, Boz!), draining entire rivers, sucking aquifers dry, breaking up delicate topsoils, etc. Some of our empty land has to grow food, or make oxygen (forests come to mind), or serve as wetlands that filter our freshwater supply, or provide wilderness that refreshes the minds and spirits of crowded urbanites. Tony suggests Winnemucca, but that's desert and already straining its ecosystem.
There are several ways overpopulation can be handled, as any biologist can tell you: greater mortality, lesser fertility, and lesser in-migration. Nature often takes the draconian solution, with mass die-offs and fertility dropping due to malnutriton of the survivors. As animals that are capable of abstract thought, we can probably do better, and look at rewarding smaller family sizes and controlling in-migration. If our survival depended on it, the whole welcoming huddled masses yearning to breathe free might be acid-washed off the statue and replaced with KEEP OUT. Our welcoming stance was predicated on a vast and thinly populated continent that awaited the huddled masses. As many experts on global warming and ecosystems have pointed out, the most powerful effect many people can have on the fate of the Earth is to stay in a fairly low-tech third world country where a person will have the lowest carbon footprint and overall demand on the planet's resources. Just by moving here, many immigrants will increase their load on the Earth ten-fold or more. They will then join us in the great enterprise of robbing our descendants of a habitable planet. So our present sanctuary role will come with a big price, in the future.