While Donald Trump continues to bad-mouth trade deals and all things Mexican (or perceived to be), Gov. Scott Walker was shaking hands in Mexico City, Xochimilco and Guadalajara last week.

That’s the difference between campaigning and governing.

Trump, the presumptive Republican nominee for president, has been playing off the fears of many Americans who worry an unpredictable and competitive global economy could undercut their employers and cost them their jobs.

Walker, no longer a candidate for president, has returned to running state government full time. Last week he pursued an important and much more realistic goal than Trump’s talk of building a nearly 2,000-mile wall between the United States and Mexico.

Walker hopes to help Wisconsin farmers, manufacturers and entrepreneurs sell more products to our longtime trading partners south of the border. More Wisconsin exports will mean more jobs here. And more commerce in both directions, while challenging for some industries, will improve the overall economies and standards of living in both countries.

Free trade encourages higher productivity, which is key to raising Wisconsin incomes. Both nations get to sell more of the products and services they’re best at producing and providing.

The GOP governor also touted Wisconsin as a great place for Mexican investment, which could help businesses expand.

Trump, in sharp contrast, has treated Mexico as a problem, rather than an opportunity. Trump has claimed he can make Mexico pay for his fanciful wall. Good luck with that. Parts of the border are vast deserts.

Trump also has insulted Mexican immigrants as “rapists” who bring drugs and crime here, and Trump recently claimed an Indiana-born judge was a “Mexican” and therefore biased against him in a court case.

Walker didn’t concentrate enough on expanding trade during his first term, so it’s good to see him pushing for greater exports now.

Trump and Bernie Sanders, another populist running for president, though as a Democrat, have railed against trade deals. Presumptive Democratic nominee Hillary Clinton has snubbed President Barack Obama, too, on his agreements with a dozen Pacific Rim nations and Europe.

But Wisconsin has gained far more from trade deals than it has lost.

“Rather than killing jobs, trade has led to substantial growth in employment, output and incomes in Wisconsin,” University of Wisconsin-Madison economics professor Noah Williams wrote this spring in Forbes magazine.

Wisconsin has enjoyed tremendous growth in trade, Williams noted, particularly in higher-wage industries such as engine building. At the same time, consumers have saved money on lower-cost imports, such as sweaters.

Wisconsin has a trade deficit in merchandise, the professor acknowledged. But our state has done very well at selling services abroad. More than one in five Wisconsin jobs are tied to trade.

Mexico is America’s economic ally. Trump’s wall, no matter how tall he imagines it would be, can’t stop globalization in the digital age, which is lifting millions of people out of poverty.