U.S. economic growth rates could double, or even triple, in the next decade if President Donald Trump’s plans produce expected sharp cuts to corporate and personal taxes, according to Steve Forbes, who ran twice for president under a platform calling for a flat tax rate.

Forbes, chairman and editor-in-chief of the eponymous financial news firm Forbes Media, said the speculation around the tax cut plan, with details expected to be outlined this Wednesday, show the scope could be a record breaker.

“In dollar terms, I hope it will be a large tax cut, the largest, the bigger the better. I think it’s going be not so much reforming the U.S. tax code, which is a horror, but simply reducing current tax rates,” Forbes told CNBC’s “Squawk Box” on Tuesday.

“On the business side we have the worst in the world, 35 percent to 40 percent. I think they’re going to try and get that below 20 percent, perhaps 15 percent,” he said. “On the personal side I think you’re going to see tax cuts across the board. And so short term, that may increase the deficit, but a growing economy cures deficits better than anything else.”

While Forbes is correct that the U.S. officially has higher corporate taxes than many industrialized countries, in practice, its largest corporations often use deductions and other maneuvers to pay taxes below official rates or to pay no federal taxes at all.

Forbes, whose presidential runs in 1996 and 2000 raised interest in simplifying the U.S. tax code, said the cuts are needed to boost economic growth, which he said in the past decade hovered at the lowest average rates since the 1930s.

“I think we can double, certainly triple what we’ve done in the last ten years. I expect if we get a good tax cut and our central bank behaves itself we could have 3 percent to 4 percent growth easily in the next few years,” Forbes said.

His comments on the Fed, which is widely expected to hike rates in December, showed he was skeptical on an aggressive rate hike path as it could blunt the impact of lower tax levels.

“I think the less the Federal Reserve, our central bank, manipulates interest rates the better and they have, as you know, a bloated portfolio of Treasury securities and the like. They’ve got to reduce that and let that money be put to work in the American economy,” Forbes said.

“So if they do that and don’t too much damage to the dollar and we get a big tax cut, the U.S. will be a growth engine once again,” he said.