Washington ? Sen. Amy Klobuchar, a Minnesota Democrat, was trying to explain recently why her state has remained “internationalist” in its soul, even as it shares the national anger about Iraq and Afghanistan. In Minnesota, she says, “internationalism is not just tolerated, it’s embraced.”

But Klobuchar warns that among her Senate colleagues, on both sides of the aisle, there are growing doubts about global engagement. Too many politicians, she told me, are moving toward “the idea that you should do nothing at all” overseas.

America’s connection to the world is one of the sleeper political issues of 2014. You can see it most clearly in the Republican Party’s internal debates, with newcomers such as Sens. Rand Paul and Ted Cruz expressing doubt about U.S. military commitments abroad, and GOP traditionalist Sen. John McCain deriding the two as “wacko birds.” There’s new wariness on the left, too, about the traditional rhetoric that accompanies defense spending.

Driving this debate is the public’s disillusionment with foreign wars, which comes through clearly in recent polling. A January sample by the Pew Research Center found that 52 percent of Americans felt the country had “mostly failed” in both Iraq and Afghanistan. That bleak assessment had been shared by just 33 percent and 34 percent, respectively, in 2011.

Frustration with Iraq and Afghanistan corresponds with a broader skepticism about foreign commitments. A Pew poll last November found that 52 percent of Americans felt the U.S. should “mind its own business internationally” and 80 percent said American should “concentrate more on our own national problems.”

The Pew findings echoed the 2013 “Transatlantic Trends” poll commissioned by the German Marshall Fund (for which I’m a trustee). That survey found a sharp decline in the percentage of Americans who said it was “very desirable” for the U.S. to “exert strong leadership in world affairs.” Just 46 percent endorsed that view last year, down from a peak of 61 percent in 2010.

Thinking about Klobuchar’s Minnesota, we can see what’s at risk in the debate about America’s foreign role. First, there’s global business: Minnesota is headquarters for 19 Fortune 500 companies, including Target, Best Buy, 3M, Medtronic and General Mills. The state’s growth markets are abroad.

For all the Garrison Keillor parodies about its Lutheran insularity, Minnesota is also linked to the world by immigrants; it has the largest Somali and Liberian populations in the country and the second-largest Hmong population. Minnesota also accounts for four of the top 20 colleges with the highest percentage of graduating seniors who have studied abroad.

The foreign-policy “establishment” may be centered on the East and West coasts, but political support for strong defense and foreign policy has been rooted in what a song by country singer Jason Aldean calls the “fly over states” of Middle America. That’s the bond that’s tested by the likes of Paul and Cruz. 

Think about some of the defining voices of global commitment over the past half-century: Sen. Howard Baker of Tennessee; Sen. J. William Fulbright of Arkansas; Rep. Lee Hamilton of Indiana; Sen. Walter Mondale of Minnesota; Sen. Henry M. Jackson of Washington; Sen. Mike Mansfield of Montana. Their internationalism spoke the flat accents of the Midwest, or the twang of the border and Southern states. 

Klobuchar argues that after a difficult decade, America needs a refreshed internationalism that recognizes its stake in the world, even as it avoids costly military commitments where possible. I’d call that balanced approach the “internationalism of the heartland,” because it sustains the deep links forged by heartland Democrats such as Hamilton, Mondale and Mansfield.

For states such as Minnesota (and I’d argue, for the whole country), disconnecting from the global grid isn’t really an option. But internationalism should be reinvented for the 21st century, so that it more clearly speaks the language of the common man and woman.

When politicians evoke global engagement, that shouldn’t be code for ever-higher defense spending. Internationalism should signify trade links that provide markets and jobs; human-rights and humanitarian policies that engage the deep religious faith of the heartland; measured security policies that protect Americans in an unstable world without busting the budget or skirting the Constitution.

Mainstream Democrats and Republicans would make a mistake to follow Paul and Cruz down the slippery slope toward isolation. But they need to refurbish the internationalist message so that it recognizes America’s mistakes — even as it protects the global connections that will allow future economic and foreign-policy success. It’s a tricky balance that politicians like Klobuchar are trying to strike, but it’s the right one for the country.