U.S. Sen. David Perdue said Monday he would insist on a final version of the tax overhaul that sets the corporate tax rate at 20 percent as House and Senate negotiators prepare to hash out their differences over the $1.5 trillion deal.

“We’ve got to get the corporate rate to where we’re going to be competitive. At 20 percent, we’re already beginning to be behind,” Perdue said after an event with the Georgia Public Policy Foundation.

Asked if he considered the 20 percent tax rate a must for his vote, Perdue said, “I think it is.”

“The U.K. goes to 17 percent next year. Eighteen is the average of Asia already. Europe is in the low 20s,” he added. “And you watch – when they woke up on Saturday morning, they started having meetings about how to get it down.”

Perdue spoke days after the Senate approved the tax bill early Saturday that would transform the nation’s tax code by cutting individual rates and slashing the corporate tax rate from 35 percent to 20 percent beginning in 2019.

Senate and House Republicans will soon head into a new phase of negotiations to reconcile different version of the legislation. President Donald Trump had also insisted on the 20 percent corporate tax rate, though he told reporters Saturday he would consider setting the rate at 22 percent.

Perdue downplayed an official analysis that showed the proposal would add $1 trillion to the federal deficits even after accounting for economic growth. He compared to the tax cut bill to a business owner investing in equipment that would pay dividends in the long run.

“I’m ecstatic today that we passed this bill. It will be so stimulative,” said Perdue, adding: “The rest of the world woke up and said, ‘Oh my God, America is back in play.’”

And Perdue, one of Trump’s most outspoken supporters in the U.S. Senate, said the measure also sent a different signal to voters.

“Whether you like the president’s tweets or not,” he said, “this agenda is starting to work.”