During an appearance on Fox Business, former Economist editor Robert Powell dispelled claims from Republican presidential nominee Donald Trump's campaign that the candidate’s tax and economic policy proposals would generate at least five consecutive years of economic growth in excess of 4 percent annually.

Powell, who is now the global risk briefing manager for the Economist Intelligence Unit, a forecasting and advisory business operated by The Economist, was interviewed on the August 24 edition of Fox Business’ Varney & Co. Host Stuart Varney opened the segment by asking for a response to Trump economic adviser Stephen Moore’s guarantee earlier this week that the massive tax cuts proposed by the Republican nominee would generate sustained economic growth far outpacing anything witnessed in the United States since 1966. Along the way, Powell poked holes in the arguments in favor of the budget-busting supply-side tax cuts Trump and other Republicans have advocated for years as a silver bullet solution to economic malaise.

Powell mocked Moore’s guarantee, noting that “the reality is money doesn’t grow on trees,” and slammed Trump’s tax plan for promising to add trillions of dollars to the debt -- far more than Democratic nominee Hillary Clinton’s proposal might. He undermined Varney’s unsubstantiated claim that cutting taxes will kickstart economic expansion, and reminded the Fox Business audience that President Reagan actually had to raise taxes to regain revenue lost to early tax cuts. Powell noted that to make up for built-in revenue losses, the rate of economic expansion would actually have to hit 10 percent or more -- which is not a “feasible” rate of growth. Most importantly, he questioned why Varney and his Fox Business cohort are gripped with so much economic anxiety when “unemployment is 4.9 percent” and the American economy is doing “relatively well” and is “a star performer” when compared with other developed countries around the world. From Varney & Co.:

Powell mentioned during the interview that The Economist does not believe either Trump’s or Clinton’s plan can meet Moore’s arbitrary growth threshold, stating that “we’re perfectly reasonable, and we don’t think Hillary Clinton will deliver 4 percent growth either.” But Powell did argue that Trump’s position on taxes and economic policy is “less responsible” than his Democratic opponent’s.

Trump’s inherent lack of responsibility is why the Economist Intelligence Unit’s global risk forecast for September 2016 ranks Trump being elected president as a threat to the global economy that is as big as “the rising threat of jihadi terrorism” and “a clash of arms in the South China Sea,” the site of a territorial dispute between China and other neighboring countries, including U.S.-allied Taiwan:

One of the things that went unsaid during the interview was how absurd it was for Varney to accept Trump’s 4 percent growth target in the first place. According to data from the Bureau of Economic Analysis (BEA), the United States has not witnessed five consecutive years of growth in excess of 4 percent in five decades. When failed Republican candidate Jeb Bush first promoted the target in June 2015, experts slammed it as “impossible” and “nonsense.” Since then, arbitrary targets of 4 or 5 percent growth have been adopted by other GOP hopefuls, including Sen. Ted Cruz (R-TX) and now Trump. For its part, Fox News has consistently fixated on setting arbitrary growth targets for the American economy in excess of 3 percent, which it claims is proof of a failed economic recovery under President Obama.