President Trump took his time to choose a nominee to head the Department of Agriculture, and he picked a good one: Sonny Perdue, a former Governor of Georgia who grew up on a farm, became a veterinarian, and has run a grain and fertilizer business.

Perdue has the potential to be an excellent Secretary of Agriculture.

Yet his job won’t be easy. He may even have one of the toughest assignments of any member of Trump’s cabinet: He’ll have to defend free trade in an administration stocked with skeptics.

President Trump swooped into office partly because of his anti-trade rhetoric. The president has called for renegotiating established trade pacts and placing new tariffs on specific imported products. Several of his key appointments have gone to outspoken protectionists.

Farmers will have an ally in Perdue, but we’ll need more than a mere ally: We need a Secretary of Agriculture who can stand his ground and make a positive case for American exports.  With the withdrawal from TPP and starting to renegotiate NAFTA, the success or failure of Perdue’s efforts could determine whether farmers enjoy a period of economic growth or suffer through an era of shrinking prospects.

A popular book on Abraham Lincoln described his administration as a “Team of Rivals”—a group of competitors who both clashed and cooperated. It appears to me that President Trump is taking a similar approach, and that Perdue can join the team and stand up for farmers and all of us who eat. During his confirmation hearings, senators will want to make sure he’s ready for the challenge.

The world will watch what we do—and China is already sending a message.

Hours before President Trump selected Perdue last week, Chinese President Xi Jinping spoke at the World Economic Forum in Davos, Switzerland. “We must remain committed to developing global free trade and investment … and say no to protectionism,” he said. “No one will emerge as a winner in a trade war.”

His remarks are at once a statement of fact—and also a warning.

A pair of Beijing-based reporters for Reuters pointed to the Global Times, “a widely-read state-run newspaper.” “If a trade war erupts”, the Times said in an editorial, China “will take on the U.S. to the end.” It added that the first casualties in a trade war would be American agriculture and aviation: “The arrogant Trump team has underestimated China’s ability to retaliate. China is a major buyer of American cotton, wheat, beans, and Boeing aircraft.”

This is a fate to avoid, but we may be closer to it than we realize because we’re arguably in a trade war with China right now—and American agriculture is already paying a price.

Last week, China imposed new tariffs on U.S. ethanol as well as DDGS, an animal-feed byproduct of ethanol. Earlier this month, it cancelled at least seven large shipments of ethanol—and more may be on the way.

This happened before President Trump’s inauguration, and it follows years of disputes over everything from Chinese tires to American poultry. In this analysis, the danger isn’t that President Trump will start a trade war as much as he’ll exacerbate one that he has inherited.

The good news is that annual sales of U.S. food products to China already top $20 billion and there is plenty of room for growth. We can choose between moving forward with trade and falling backward in an endless series of costly retaliations.

This is no choice at all, of course.

Secretary-Nominee Perdue knows China. As governor, he made a series of trips there, recognizing that Georgia businesses sold more goods and services to China than any other country except Canada. He’ll also have an ally in Governor Terry Branstad, who is Trump’s nominee to become Ambassador to China—and who, as governor of Iowa, appreciates the importance of agriculture, food and the ability to trade freely.

I’ve depended on them my whole life as a farmer—and I’m getting ready to plant my 45th crop. I’ve also relied on advocates in the federal government to open new markets.

I’m confident that Sonny Perdue is up to the task.