President Trump had promised to quickly pass a replacement for the Affordable Care Act. He later acknowledged that health care is “an unbelievably complex subject.”

He is finding the same goes for global trade.

Trump, who had campaigned on a promise to save U.S. jobs by getting tough on trade deals, seems to have learned that global commerce is hardly a silo. Pulling on one end of the economy inevitably impacts the other, sometimes in unexpected ways.

Take the North American Free Trade Agreement. Trump says he wants to renegotiate the deal because he thinks Mexico is stealing American jobs by luring U.S. companies with its low-cost labor. He has threatened to slap border taxes and tariffs on Mexican imports.

But Mexico buys billions of dollars of goods from U.S. firms, so the country will surely retaliate with its own tariffs, former Mexican President Vicente Fox said in an interview Wednesday.

“Trading is not a zero-sum game,” said Fox, who was in San Francisco to speak at the Commonwealth Club. “Trading is to the benefit of two nations.”

“We don’t want trade wars,” he said. “But if he decides on a border tax, every action has a reaction. ... American farmers, you will lose a lot of money.”

Indeed, Trump no longer seems to support a plan to finance construction of a border wall with a tax on Mexican goods.

In addition, he recently signaled support for the Export-Import Bank, which finances exports to developing countries like China and India. Republican conservatives in Congress have long wanted to eliminate the agency, calling such financial support as “corporate welfare.” But the Export-Import Bank has produced a profit for taxpayers, something that Trump likes, especially as he tries to find ways to pay for deep tax cuts — though he did name a sharp critic of the bank as its president.

Back to Gallery Trump is finding that trade, like health care, is quite hard 3 1 of 3 Photo: Beck Diefenbach, Special to The Chronicle 2 of 3 Photo: Beck Diefenbach, Special to The Chronicle 3 of 3 Photo: Beck Diefenbach, Special to The Chronicle





Trump also appears to be backing away from a campaign promise to name China as a currency manipulator — a claim unmoored from current reality, according to authorities like S&P Global Ratings.

The reason? Trump needs China to restrain North Korea from testing nuclear weapons.

“Why would I call China a currency manipulator when they are working with us on the North Korean problem?” he tweeted.

Any move to punish trading partners will hurt the U.S. economy — especially in the Bay Area, where hundreds of thousands of jobs depend on exports. Until now, what Trump has refused to acknowledge is that the global economy, with its interlocking supply chains, is beyond the reach of any one person or country.

“You cannot change the global economy just because you want to change it,” said Mauro Guillen, a professor of management at the University of Pennsylvania’s Wharton School. “These are complicated issues.”

For example, Mexico is a top destination for U.S. energy and agricultural products. The U.S. Trade Representative’s office estimates that Mexico purchases more than $2 billion worth of corn and more than $1 billion worth of beef from American farmers and ranchers, many of whom live in Midwest and Southern states that voted for Trump.

Because of this, elected leaders in those states have “a stake in preserving the status quo,” according to a recent report by global risk analysis firm Stratfor.

And Mexican goods exported to United States like cars and medical devices often include components made in America. The Center for Automotive Research estimates that ending NAFTA and imposing tariffs would cost America 31,000 jobs in the auto sector alone.

If Trump cares about jobs, in other words, he needs to care about trade.

“Who wants General Motors or Ford to go broke again?” Fox said. “Who wants more taxpayer money to rescue” these companies?

California’s exports to Mexico totaled $25.2 billion in 2016, including machinery, airplane parts, almonds and semiconductors, according U.S. Census data. Mexico and Canada account for more than $41 billion, or 25.3 percent, of state exports.

California sent $14.4 billion worth of goods and services last year to China, the world’s second-largest economy.

Wendy Cutler, the former acting deputy U.S. Trade Representative who is now managing director of the Asia Society Policy Institute’s Washington office, says that striking trade agreements can help strengthen a broader relationship. For example, the U.S. and China for years have been negotiating a bilateral investment treaty that would theoretically address many of Trump’s complaints about the Chinese market: access to specific industries and protection of intellectual property.

You would think this would play to the president’s perceived strength as a deal maker. And the administration has previously signaled that it wants to negotiate deals with individual countries instead of forging large trade agreements with several nations.

But to be a real deal maker, Trump needs to take a pragmatic, holistic approach to trade and ditch the populist, protectionist tone of his campaign. That’s starting to happen; whether he can keep it up, and bolster jobs in the U.S. and abroad rather than simply using trade as a bargaining chip, remains to be seen.

Thomas Lee is a San Francisco Chronicle columnist. Email: tlee@sfchronicle.com Twitter: @ByTomLee