Q&A: will Donald Trump’s immigration plan blow up the US economy?

An immigration plan released by Republican presidential frontrunner Donald Trump over the weekend has been embraced by conservatives as a starting point for Republican candidates preparing to make their pitch to voters in 2016.

Here’s a look at what’s in Trump’s plan and what it would mean for the US economy.

Q: What’s in the plan?

A: For starters, build a permanent border wall between the US and Mexico that Mexico “must pay for”.

Q: Will Mexico agree to that?

A: The plan proposes various sticks to force Mexico to cooperate, such as impounding all remittance payments to Mexico from illegal wages earned in the US. Total remittances to Mexico in 2014, according to the World Bank, were $25bn, with most of that coming from the US.

Q: But how would they be able to tell which remittances were from illegal wages and which were from somebody who just wants to send money to Mexico?

A: The plan does not get into that. An army of auditors and investigators?

Q: Isn’t Mexico an important US trading partner and neighbor, and wouldn’t it be reckless to make such a dramatic change to US-Mexican relations?

A: Mexico is the second-largest destination on Earth for US exports – Mexicans buy about $240bn in US goods each year – and is increasingly important to US companies as a manufacturing and labor center. Meanwhile many US employers depend on undocumented migrants from Mexico.

A spokesman for Mexican president Enrique Pena Nieto told Bloomberg last week that the assertion that Mexico would pay for a border wall is “false”. “It reflects an enormous ignorance for what Mexico represents,” spokesman Eduardo Sanchez said, “and also the irresponsibility of the candidate who’s saying it.”

Q: What else is in Trump’s immigration plan?

A: Increase the number of immigration and customs enforcement officers, put in place an employer-based e-verify program and deport “criminal aliens”.

Q: Those sound like pretty run-of-the-mill prescriptions? Hasn’t even Barack Obama called for prioritizing criminals for deportation on immigration grounds and for extending e-verify and for more ICE officers?

A: Yes.

Q: What about a path to citizenship for undocumented migrants who may have lived in the US for years? I heard Trump favored that, and he was catching heat from the right for it?

A: Trump in the past has called for evaluating the desirability of undocumented migrants living in the US “ on a case-by-case basis ” before deciding whether to deport them. To some conservatives that has sounded suspiciously like an offer of “amnesty” for some migrants.

Trump’s current plan does not address what to do about the estimated 11.7m undocumented migrants currently living in the US.

But earlier this year, Trump said that Obama’s executive order not to pursue the deportation of undocumented migrants who arrived in the US as children, or of their families, was illegal. “Our president broke the law when he did what he did,” Trump told the Conservative Political Action Conference (CPAC). “And you’re going to have to take a tremendously strong action or you’re going to have people just flowing into this country worse than it’s ever been.”

Q: What else is in the plan?

A: Ending birthright citizenship for undocumented migrants and changing laws for H-1B visas to incentivize US tech companies to hire Americans first.

Q: Good ideas?

A: Ending birthright citizenship, which some analysts believe would increase illegal immigration, would require a constitutional amendment, which would require a congressional supermajority (two-thirds of the vote in each house of Congress) plus the assent of 38 states.

Trump’s proposal for H-1Bs involves increasing prevailing wage estimates for math, sciences and technology jobs, which would in effect make jobs associated with those visas more high-paying, which, the argument goes, would stop companies from looking to foreign labor pools. But the editors of theNational Review think the plan “would more likely than not just invite more meddling from the same lawyers and bureaucrats who already exercise outsized importance in H-1B decisions”.

Q: So what would Trump’s immigration plan cost the American economy?

A: Do you want the ornamental Ts all along the top of the wall to be coated in real gold leaf or just the fake stuff?

It’s hard to answer this question, because of how impracticable the Trump plan seems to be and how unpredictable the results would be. What would be the cost to US manufacturers to lose Mexico as an export market?

The Congressional Budget Office estimated that enacting a 2013 Senate immigration reform bill, which would have granted work permits to some undocumented immigrants, would have increased real GDP by 3.3% in 2023 and 5.4% in 2033. By that analysis, the Trump plan would cost the US economy in terms of unrealized growth.

If you believe that immigration from Mexico is good for the US economy, you aren’t a likely Trump voter. But you do have the support of many economists, who say that immigration to the US has increased GDP and economic productivity and strengthened key sectors such as technology, tourism, agriculture, technology and housing.

Thinktanks such as the progressive Economic Policy Institute say that undocumented migrants in the US decrease overall budget deficits, pay billions of dollars more into social security annually than they take out and have a minimal impact on wages, even low wages. Meanwhile the cost of deporting the millions of undocumented immigrants currently in the US has been estimated at $285bn over five years.

Q: Apart from the hostility and isolationism a border wall would represent, would it really be a smart move, just in terms of how much it would cost to build? Isn’t illegal immigration from Mexico falling anyway?

A: How much would building a border fence of the kind Trump describes cost? It’s hard to say. Billions and billions. The border is almost 2,000 miles long. A lot of it isn’t fenced at all; hundreds of miles of it has single-layer fencing that does not seem to rise to the level of a “permanent border wall”.

Meanwhile, thanks to economic growth in Mexico and some difficult years for the US economy, illegal immigration to the US is down. The population of unauthorized migrants from Mexico in the US peaked in 2007. Immigrants from Central America and other countries cross the southern border to enter the US illegally. But Trump is not proposing that Guatemala pay for a border wall.