If confirmed, Sonny Perdue, the last nominee to President Trump’s cabinet, will take on a task that just got monumentally more difficult.

As secretary of agriculture, Perdue will be among those dealing directly with the fallout if Trump follows through on a threat to slap a 20 percent import tax on goods from Mexico, a top trading partner for the U.S. and, not incidentally, Minnesota. Trump floated the proposal — which a spokesman later said was being weighed against other options — just days after he pulled the U.S. out of the Trans-Pacific Partnership, which this page and many Republicans long favored as a way of lowering trade barriers.

Perdue will face a host of challenges, although the increasingly fragile relationship with a key trading partner for the U.S. and, not incidentally, Minnesota, undoubtedly has just risen to the top.

There are several reasons to be hopeful that Perdue, a former Georgia governor who was born on a farm and who made his fortune in agribusiness, will be a strong voice on trade and educate the new president on the delicate balance among nations that have ties that go back as far as those of the U.S. and Mexico. Congress, which will have the final say on any import tax increase, should exercise extreme restraint on measures that could touch off a trade war or worse, and Perdue should lend his voice to those efforts. No one is opposed to better trade deals, but the difficulty of achieving such an aim should not be underestimated.

Minnesota has much to fear from a trade war. It is the fourth-largest agriculture exporter among the states. And China, another Trump target, is this state’s top buyer of soybeans and feed and its third-largest export market overall — right behind Mexico.

Perdue should also be mindful of immigration. Minnesota farms, like those across the country, depend on immigrant labor. This nation desperately needs comprehensive immigration reform that provides a path to citizenship for immigrants who have established lives here, paid taxes and stayed out of trouble. Minnesota farmers, in particular, can readily attest to the difficulty of finding and keeping workers willing to do the hard labor demanded in agriculture.

Then there is the farm bill, set to expire in 2018, which covers crop insurance, price supports and the massive school lunch and food stamp programs that make up its bulk. Perdue should resist efforts to separate the nutrition programs, as some Republicans have sought. The coalition of rural and urban/suburban lawmakers has helped foster bipartisan support for the bill since the early 1970s, and that bipartisanship will be needed in this Congress.

The conservative Heritage Foundation, a think tank that has provided plans for some early Trump administration positions, has pushed not only to separate the programs but to eliminate sugar tariffs that protect the American sugar industry and to limit crop insurance to cover only major losses. There may be some room to revisit the longstanding practice of agriculture subsidies, but again, caution must be exercised if the U.S. is to maintain a stable, homegrown food supply.

That will be especially important if other nations choose to retaliate with punitive tariffs of their own. Gary Wertish, the new president of the Minnesota Farmers Union, notes that even after a good year, corn didn’t cash flow in 2016. “We need subsidies to ensure stability,” Wertish said. “Farmers just want to stay in business.”