Secretary of State Mike Pompeo is unhappy. Sen. Chris Murphy (D-Conn.) met with Iran’s foreign minister just as Pompeo prepared to meet with the Saudis to discuss confronting Iran. Pompeo fumed, “This is the foreign minister of a country … who is the largest world sponsor of terror. … I hope they were reinforcing America’s foreign policy and not their own.” Murphy promptly shot back on Twitter about congressional power: “We set foreign policy too.”

Spats like this increasingly shake up America’s bipartisan foreign policy consensus. In 2015, when Republican senators sent a letter to Iran’s supreme leader in a naked attempt to undermine the Obama administration’s nuclear negotiations, a former Clinton administration official tweeted that Republicans are “blazing new trails in politicization of foreign policy.” Last summer, the Democratic-led House passed a bill to check President Trump’s belligerence with Iran. House Minority Leader Kevin McCarthy (R-Calif.) accused Democrats of playing politics, scolding, “America’s national security is not a game.”

Many leading commentators sound a similar alarm. Richard Haass, president of the Council on Foreign Relations, opined that a “polarized US will be less able to act” in the world. In a survey of foreign policy experts by the Chicago Council on Global Affairs, political polarization was more likely to be named a “critical threat” to U.S. national security than Iran, North Korea, China or Russia. The notion that Americans should be unified on foreign affairs questions is, somehow, still sacrosanct.

But bipartisanship is no indicator of the wisdom of a particular policy. And plenty of terrible foreign policy decisions have escaped scrutiny in its slavish pursuit.

The dust-up between Pompeo and Murphy reflects an important partisan difference in how many view our relationships in the Middle East. In Washington, Democrats soften their outlook on Iran and harden it on Saudi Arabia, while Republicans do the opposite. This difference of opinion is real and legitimate and should be aired, because, as a new study by the Eurasia Group Foundation, where I am a senior fellow, shows, American foreign policy differences are rooted in public opinion. Republicans are 13 percent more likely than Democrats to believe that Iran presents a significant threat to peace in the Middle East. Democrats are roughly 10 percent more likely than Republicans to believe the same about Saudi Arabia. To be sure, Iran, a long-standing U.S. adversary, is the country most considered a threat to Middle East peace across party affiliation. Still, this slight but significant partisan variance leads to a lot of pearl-clutching among a foreign policy establishment that prizes consistency.

Bipartisanship is alive and well when it comes to pumping billions of additional dollars into America’s bloated military budget. Chasing spending records set during the Korean and Vietnam wars, 188 House Democrats voted with Republicans in December to give the Pentagon an additional $22 billion in 2020 (for a grand total of $738 billion). House Democrats do a poor job of representing Democratic voters, 90 percent of whom want to decrease military spending or at least keep it level, according to our survey. This should be cause for regret, not praise. Elected officeholders should represent — or at least heed — the views of their constituents. (Democrats aren’t the only voters getting short shrift in the name of foreign policy consensus. Most Republicans preferred to keep military spending level as well.)

Perhaps the toughest foreign policy challenge of the new decade is China’s rapidly increasing international influence. How American political leaders define and address that challenge is crucial to how we, as a nation, negotiate our vital interests and understand our values. So it is — and must be — a matter of American politics, not only geopolitics.

Crucially, Americans don’t all see that challenge the same way. Asked about their preferences for responding to a rising China, a slim majority of Republicans think the United States should move more troops onto bases in allied countries to check its regional influence. A significant majority of Democrats and independents believe that the United States should reduce its military presence in Asia while transitioning regional allies toward assuming greater responsibility for regional security. The Pew Research Center, too, found partisan divisions as well as generational ones: When it comes to limiting the influence of — or maintaining the U.S. military advantage over — other countries, younger generations are far less supportive than older ones. With so much at stake, this should be the start of a spirited debate.

But some experts disagree. Lamenting that foreign policy debates are “infused with and defined by partisan divisions,” a new report by the bipartisan Center for a New American Security frets that “if policy toward China falls prey to similar dynamics, the United States will fail to rise to the China challenge.” (That challenge “is going to require more cost and more risk than we anticipated,” according to one of the report’s lead authors.) Foreign policy pooh-bahs too often see principled political disagreements as a source of weakness rather than an example of the pluralism we try to uphold to the world.

To be sure, we need national security and foreign policy expertise more than ever, and our political leaders should be influenced in different ways by both expert and public opinion. We should not careen to the other extreme and conduct foreign policy by referendum. We saw what happened with Brexit. Voters elect their representatives for their reasoned judgment, not as mere conduits. This is in part so voters needn’t be broadly informed about highly complicated or technical issues like the destabilizing effects of antisatellite missile systems or the pros and cons of a nuclear no-first-use policy. But too often, policymakers use that relative ignorance as an excuse to insulate themselves from the more general preferences of the public they’re meant to serve.

Meanwhile, an ardent commitment to bipartisanship has given us: the vote to authorize the Iraq War, the stubborn and costly refusal to leave Afghanistan until it shares our values and form of government, and the diplomatic and political isolation of North Korea, which created the conditions for it to become a nuclear-armed country.

In 1948, after bowing out of a bid to defeat Democratic President Harry Truman, Sen. Arthur Vandenberg (R-Mich.) declared, “We must stop politics at the water’s edge.” In other words, we should confine our disagreements to domestic policy and project unity to our foreign friends and foes. But that unity was merely a product of the geopolitical realities at the dawn of the Cold War. More often, an elite consensus feeds stale policy, allows bad ideas to go unchallenged and narrows the range of new proposals welcomed as legitimate. There’s a word that describes a politically powerful person making a high-minded exhortation to “stop politics.” That word is not “democracy.”

There is no tradition of — nor enduring allegiance to — bipartisan consensus in America’s international relations. Nor should there be.