A number of industries that depend heavily on cheap immigrant labor would be devastated -- especially agriculture. "There would be an abrupt drop in farm income and a sharp rise in food prices," said John McLaren, professor of economics at the University of Virginia with expertise in international trade, economic development and the political economy.
Companies that sell to the immigrant population would be affected as well, leading to decreased revenues for local businesses and a loss of American jobs.
"Immigrants, whether they are legal or illegal, always spend a portion of their earnings in the location where they have their jobs," McLaren said. "And in a lot of our urban centers, this is actually an important part of the economy."
He pointed to the case of Postville, Iowa, where in 2008 U.S. Immigration and Customs Enforcement (ICE) raided a slaughterhouse and meat packing plant, detaining 389 undocumented workers (and jailing 300 of them). The raid caused most of the more than 1,000 immigrants not caught to leave the town of 2,300, devastating the local economy in the process.
He also noted his own research, which suggests each immigrant creates 1.2 local jobs for local workers, most of which go to U.S. natives. "Obviously, those jobs would disappear if the undocumented were just yanked away," he said.
It is worth noting that Trump appears to have backed away from his mass deportation stance slightly, outlining priorities that would lead to the deportation of what The Washington Post estimates would be 5 million to 6.5 million immigrants. He has warned, however, that "anyone who has entered the United States illegally is subject to deportation."
Trump has also discussed reducing the number of jobs held by legal immigrants, namely by increasing the prevailing wage requirements for H-1B visas (visas that allow U.S. employers to recruit and employ foreign professionals) -- an element of his plan that is often overlooked. His thesis is that doing so would force companies to give jobs to domestic employees instead of overseas workers. The maneuver would benefit some, but not most.
"If I'm an American software programmer, I probably would benefit somewhat from making it harder for highly-skilled software programmers from elsewhere," McClaren said. "It's really hard to argue that the country, as a whole, benefits from that. It would be bad for most Americans, and it certainly would be bad for corporations."
An extreme anti-immigration policy could also cause collateral damage to the American image. "What's the American brand after we've rounded up 11 million people and sent them packing?" said Jim Pethokoukis, a columnist and blogger at the American Enterprise Institute, a center-right think tank based on Washington, D.C. "Do people still view America the same way?"
Perhaps it's a good thing the real estate magnate's immigration plans are essentially impossible to implement in full.
Tax Cuts for Everyone, and Deficits, Too
Trump's tax plan, unveiled in September, is perhaps the most detailed proposal he put forth while campaigning. It entails implementing tax cuts across the board, though some in the middle class would see their tax bills go up.
"His tax plan is one of the most dynamic and pro-growth tax plans out there," said Merrill Matthews, resident scholar at the Institute for Policy Innovation, a Texas-based, right-leaning think tank. "You would find a huge amount of new business investment and companies willing to put their money out there to begin growing the economy."
Trump's tax plan stacked up fairly well against his fellow Republican presidential primary contenders. It wasn't as drastic as proposals put forth by Ted Cruz and Ben Carson but did, like most GOP tax structures, favor the rich.
Perhaps the biggest distinguishing feature of Trump's proposal is his hard cap on business taxes at 15%, which might be especially appealing to freelancers and the self-employed.
But there's a catch: Trump's tax plan would reduce revenue enormously, and the federal budget deficit would almost inevitably skyrocket.
Nonpartisan tax research group the Tax Foundation calculated that Trump's plan in its original form would cut taxes by $11.98 trillion over the course of a decade. It would lead to 11% growth in the GDP, 6.5% higher wages and 29% larger capital stock as well as 5.3 million jobs. However, it would also reduce tax revenues by $10.14 trillion, even when accounting for economic growth from increases in the supply of labor and capital.
"That tax cut would produce faster economic growth and a bigger economy -- as long as you pay zero attention to the fact that it would dramatically increase the deficit and budget debt," said Pethokoukis.
Trump in August adjusted his platform, calling for a top income tax rate of 33% rather than a past plan for 25% as well as the full expensing of capital investment and a deduction for childcare costs.
An updated version of the Tax Foundation's analysis determined Trump's more fleshed-out tax plan would reduce federal revenue by between $4.4 and $5.9 trillion, depending on how it handles pass-through businesses. The group noted that the change would reduce the revenue loss from his original plan, but it would depend significantly on how wide the new bracket thresholds are.
Trump has promised to reduce spending, though he hasn't explicitly said how. Moreover, he has said he will maintain entitlement programs like Social Security and Medicare, two of the costliest parts of the federal budget.
"If there weren't any spending cuts that materialized, you would see the deficit widen substantially the moment the plan was enacted," said said Alan Cole, an economist with the Center for Federal Tax Policy at the Tax Foundation.
In the face of such an enormous deficit, creditors might begin demanding higher interest rates on U.S. bonds, and the markets would be spooked.
"I can't imagine markets would react well to it. I can't imagine global investors looking to relocate will look on a United States that is driving deliberately over a fiscal cliff," said Holtz-Eakin. "Sending the U.S. into a debt spiral where you're borrowing interest on previous borrowing will generate a market reaction that will be far from benign and that will, I think, in the end overwhelm the beneficial effects."
Of course, just because Trump hasn't yet explained how he will cut spending doesn't mean he won't. "It's not unusual for a politician to say, 'I'm going to cut spending,' and not give specifics," Matthews said.
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