Is Donald Trump’s economic policy a magical way to generate hyper growth, sprout millions of new jobs and cut the nations’ debt — or is it simply a mirage?

Trump claims his “America First” plan will grow the U.S. economy over the next decade by a whopping 3.5 to 4%, generating 25 million new jobs.

For perspective, the 1980s much lionized Reagan-era only generated 16 million. If Trump can deliver, who wouldn’t want this economic utopia? Unfortunately, his policy is not grounded in reality.

To start, his flawed plan calls for renegotiating existing trade deals, even proposing a 45% tariff against China. This approach would weaken the U.S. economy as nations quickly retaliate, overall trade shrinks and jobs are lost. History should not be ignored.

Despite warnings, in 1930, U.S. President Herbert Hoover signed the Smoot-Hawley Tariff Act, deepening the Great Depression.

At $18 trillion, the U.S. economy is the world’s largest, equaling 22% of the global economic pie. Given world GDP through 2020 is expected to hover around 3%, the U.S. economy is locked in a slow-growth world.

Trump ignores that the current economic expansion, now seven years old, is the third longest in U.S. history.

It is highly likely that a downturn will occur in the next few years. Even if a recession could be avoided, it would be extraordinary if U.S. GDP reached 3% — a feat that hasn’t been attained in the last decade.

The Republican presidential nominee’s anti-globalization bluster is also dangerous. The World Bank and IMF emerged from the lessons learned in the 1930s about the destructive cycle unleased when nations have divided economies.

His plan would threaten over 70 years of proven work that has boosted long-term economic wellbeing. Withdrawing from global trade would depress the world economy and trigger a drop in U.S. GDP. For each half percentage point drop, over a half million jobs would be lost.

Meantime, the heart of Trump’s plan is to revise the U.S. tax code, slashing the corporate tax rate to 15% from 35%. Even if his campaign’s estimates are assumed accurate, government tax receipts would fall over the next decade by $4 trillion.

Nonpartisan estimates put it closer to $9 trillion. Such thinking assumes that tax cuts inevitably deliver economic growth — the Ronald Reagan-era “trickle-down economics” myth. From the George W. Bush tax cuts in early 2000s to the cut enacted by Barack Obama in 2009, there is no conclusive evidence that doing so bring home the economic bacon — at least not for the 99%.

In reality, tax cuts without compensating growth would add trillions to the U.S. deficit. Even when Reagan slashed corporate taxes, his lowest rate was 28%, considerably higher than where Trump wants to go. And while Reagan-era GDP growth averaged over 3%, his tax cuts eventually swelled national debt. Under this 40th president, the U.S. morphed from the world’s largest creditor to the world’s largest debtor nation.

Under the Trump scheme, the top personal tax rate would drop to 33% from 39.6% and the number of tax brackets would be collapsed from seven to three. In contrast, Democratic presidential nominee Hillary Clinton proposes to increase the rate for the top-income earners, creating a new bracket — for example, a surcharge for those making over $5 million a year to 43.6%, a 4% increase.

Recklessly, Trump is proposing these tax cuts without offsetting cuts to the fastest growing government spending areas — healthcare programs, Social Security, Medicare, Medicaid and public pensions. The Committee for a Responsible Federal Budget estimates this could add $5 trillion in the next decade.

As the U.S. deficit mushrooms, financing costs of servicing this debt will soar — a cost that will be compounded as the Federal Reserve Bank starts its overdue rate-hiking cycle in December. If government tax revenue is declining and costs rising, the only way to fill this gap, without growing debt, is through tax hikes.

Reagan eventually saw the light, raising taxes during his second term.

Further, Trump claims that restricting immigration will create economic prosperity. But history has proven this will have the opposite effect.

Immigration helps increase the labor pool of skilled and unskilled workers. More people working, paying taxes, buying homes, and starting new businesses lifts U.S. economic growth. Due to existing demographics, greater restrictions on immigration would only exacerbate the current labor shortage and hobble further economic growth.

Trump also wants to gut regulation on the banks that helped create the worst recession since the Great Depression. Targets to dismantle include the Dodd-Frank Act put in place to protect against the next big financial crisis, and the U.S. Consumer Financial Protection Bureau.

This is ill-advised because big banks that took too much risk are still a drag on the global economy with Deutsche Bank the poster child. The recent scandal at Wells Fargo Bank where over 5,000 employees cheated millions of customers is also a stark reminder of the need for stronger not weaker consumer protection.

There is good reason few economists have endorsed Trump’s economic plan.

It ignores history, uses failed policy, promises what is impossible and, if implemented, would cause significant harm to an ever strengthening U.S. economy.

Mark T. Williams teaches finance at Boston University, is a former Federal Reserve Bank Examiner and author of “Uncontrolled Risk” about the collapse of Lehman Brothers and the key drivers of the financial crisis.