There are many reasons to fear the prospect of a second term in the White House for Donald Trump. From his reported plans to purge the government of career experts and replace them with hard-core loyalists to his habit of inciting violent riots when things don’t go his way, the list is pretty much endless. It also includes things like his apparently strong desire to bomb various countries and then claim the US didn’t do it. Also high up there? The massive tariff he wants to slap on all imports to the United States that both liberal and conservative economists are warning would lead to economic disaster.

The idea for a “universal baseline tariff” was reportedly discussed at a dinner last week at Trump’s New Jersey golf course attended by former White House economic adviser Larry Kudlow—best known for claiming recessions are a good thing—and outside adviser Stephen Moore, whose short-lived nomination to the Federal Reserve Board was dubbed “truly appalling” and a worse idea than nominating Ivanka Trump for the job. (Newt Gingrich was also there, according to The Washington Post.) A day later, the former president went on Fox Business and called for an “automatic“ tariff of 10% on all foreign goods coming into the country. “I think we should have a ring around the collar” of the US economy, Trump said during the interview. “When companies come in and they dump their products in the United States, they should pay, automatically, let’s say a 10% tax…I do like the 10% for everybody.”

Trump was famously obsessed with hitting various countries with tariffs during his first term in office, and if you thought his decision to do so then was a bad idea, well, just wait:

Economists of both parties said Trump’s tariff proposal is extremely dangerous. Adam Posen, president of the Peterson Institute for International Economics, a Washington think tank, called the idea “lunacy” and “horrifying” and said it would lead the other major economies around the world to conclude the United States cannot be trusted as a trading partner. Although aimed at bolstering domestic production, a 10 percent tariff would hurt the thousands of U.S. firms that depend on imports, while also crippling the thousands of U.S. firms that depend on foreign exports, Posen said.

The United States today imposes an average tariff on imports of just above 3 percent, according to Posen. That number is higher for some countries, with goods coming from China facing an average import duty of 19 percent.

“You would be depriving American families of an enormous amount of choice, making their lives much more expensive, and putting millions of people out of work,” Posen told the Post, and, in case it wasn’t clear, making things significantly more expensive for Americans and “putting millions of people out of work” are generally considered to be bad things. But hey, don’t take Posen’s word for it. What does a conservative economist who used to work for Trump think of the idea?

“A tariff of that scope and size would impose a massive tax on the folks who it intends to help,” Paul Winfree, who served as Trump’s deputy director of the Domestic Policy Council and is currently the president of a center-right think tank, told the Post. “It would get passed along through higher prices at a time when the Federal Reserve has had difficulty limiting inflation.”

Another reason to fear the implementation of “universal baseline tariff”? The door it would open for possible corruption, even though Donald Trump would obviously never knowingly allow such a thing to occur on his watch. Per the Post:

Trump could use unilateral authority to exempt whatever countries he chooses from the automatic import tariffs. It would create enormous opportunities for influence-peddling, Posen said, following four years of a Trump presidency in which Saudi Arabia and other nations sought to steer Trump by frequenting his private businesses. “It is a recipe for corruption,” Posen said. “They will decide that whoever cozies up to Trump, or whoever his commerce secretary is, will get the exception.”