In the wake of the election, the immigration reform conversation has gotten sidetracked into the sort of odd topic of whether a more pro-immigration position would be politically helpful to Republicans. Not to be totally humorless about it, but the actual best reason to liberalize immigration policy is that doing so would be good for America and the world. There's a good Wall Street Journal story today headlined "Heartland Draws Hispanics to Revitalize Small Towns" which is among other things a reminder that when you get down to a smaller scale than the nation-state, people's intuitions about immigration get a lot sounder.
Clearly a small town that's losing population is going to have serious problems. It's not all "yippee, more jobs for those of us left behind!" What happens instead is that the value of the town's existing stock of capital goods (primarily buildings) declines, forward-looking investment crashes, residents lose income flows, and businesses have fewer customers.
That's because a modern service economy is made of people.
Whether you're a plumber or a waitress or a nurse or a teacher or an accountant or a barber you want to have customers around. If a bunch of people say "hey, this is a nice town let's move there" then local investment booms since you need more houses and auto repair shops and restaurants and schools and hospitals to accommodate everyone. And this is all basically true on a national scale, except that the (large) income increases that accrue to the immigrants themselves are also broadly beneficial. Even if you're not involved in local service production, there's going to be more demand for cars, mobile apps, online political commentary, branded t-shirts, and James Bond movies in a richer world.
Political writers have an unfortunate issue to treat immigration as a kind of niche ethnic politics issue, but even among Hispanics only a relatively small minority cite it as the most important topic. What people of all ethnicities care about is economic growth and the welfare of their families. Immigration has a substantial—and positive—impact on that, and that's what matters most.