Pittsburgh members of Bend the Arc, the national movement of progressive Jews seeking to build a more just society, announced after the slaughter of 11 Jewish worshipers who had gathered on Shabbat morning at the city’s Tree of Life synagogue that “President Trump, you are not welcome in Pittsburgh until you fully denounce white nationalism.”

Trump did not answer the call to renounce the dog-whistle messaging that seeks to stoke fear and hatred as a political tool. Instead, he made an unwelcome visit on Tuesday to Pittsburgh, where he was met with mass protests by righteous people of all faiths. The thousands who challenged the president’s decision to impose himself on a city in mourning marched behind banners that called on Trump to

• Fully denounce white nationalism, • Stop targeting and endangering all minorities, • Cease your assault on immigrants and refugees, and • Commit yourself to compassionate, democratic policies that recognize the dignity of all of us.

The president was given an opportunity to stand on the right side of history. He failed to embrace it.

What happened in Pittsburgh three days after the worst anti-Semitic attack ever experienced in the United States summed up the cognitive dissonance in Trump’s America.

Yet there was no resolution. As he prepared to travel to Pittsburgh, Trump was busy picking a new fight over immigration policy—with an absurd proposal to use an executive order to override the birthright-citizenship protections contained in the US Constitution. And, in short order, the president was back on the campaign trail, stirring divisions and hoping to animate “the base” of a Republican Party that has for the most part embraced a win-at-any-cost approach to the 2018 elections.

Bend the Arc: Jewish Action recognized the crisis even before Tuesday’s face-off in Pittsburgh, noting in its national call to action that this is about much more than Donald Trump. “The Trump administration, the Republican Party and their enablers have provoked violence against our communities. Our blood is on their hands,” the group declared. “It is time to rise up together to demand our safety. We refuse to be divided. We refuse to be isolated from each other. We will outlive their hatred.”

The mention of the Republican Party got to the heart of the matter. While Trump chose not to pay attention to pleas from Pittsburgh, he cannot ignore results from an election that will determine the scope and character of his party’s presence in the next Congress. One result could produce the clearest of all signals regarding the urgent need for the president and his party to unequivocally reject nationalism and dog-whistle politics.

Northwest Iowa’s Fourth Congressional District is far from Squirrel Hill. And it is far more conservative politically than Pittsburgh. Though it was historically competitive, the district swung hard toward the Republicans in 2016, giving Trump a 61-34 win over Hillary Clinton. Yet it is this district that has the potential to renounce white nationalism in a way that cannot be ignored by the president or his party.

The congressman from the fourth district, Republican Steve King, is the most prominent proponent of far-right extremism within a party that have been infected with hateful demagoguery in recent years. Long a favorite of the alt-right, King displays a Confederate flag in his Washington office and makes no secret of his enthusiasm for contemporary nationalist movements.

King has a history of mouthing the talking points of those movements: ranting about Western civilization as a “superior culture,” claiming that immigration is leading to the “decline” of the West, and saying he wants “an America that’s just so homogeneous that we look a lot the same.” King tweets lines like “Diversity is not our strength” and “Assimilation has become a dirty word to the multiculturalist Left,” and echoes the anti-immigration meme: “we can’t restore our civilization with somebody else’s babies.”

The eight-term congressmen, a regular guest on right-wing cable and broadcast outlets since he came to Congress almost two decades ago, found himself under harsh scrutiny following the Pittsburgh attack, as media outlets began exploring his links with the Freedom Party of Austria. That party was led in the post–World War II era by Anton Reinthaller, a former Nazi minister for agriculture and undersecretary of state to the Reich Ministry of Food and Agriculture who served as an honorary Brigadeführer in Hitler’s SS. Today, the party is in the forefront of the European far-right resurgence; its leader, Austrian Vice Chancellor Heinz-Christian Strache, claims that his membership in a neo-Nazi group as a youth was “naive,” yet the Jerusalem Post reported this year that “[Austrian] anti-Semitism watchdogs have said the FPO was involved in dozens of incidents in recent years, and the party continues to campaign on strongly anti-immigrant lines.”

In February, Reuters reported that a top Freedom Party candidate “had been fending off a scandal after a newspaper revealed that a fraternity that he used to help lead had distributed a songbook that joked about killing Jews.“ (The candidate reluctantly resigned his party posts.)

What does King say? After the Pittsburgh shootings, he defended his engagement with the Austrian right and said, “If they were in America pushing the platform that they push, they would be Republicans.” That was too much for Ohio Congressman Steve Stivers, the chair of the National Republican Congressional Committee, who said Tuesday that “Congressman Steve King’s recent comments, actions, and retweets are completely inappropriate. We must stand up against white supremacy and hate in all forms, and I strongly condemn this behavior.” But, so far, Stivers is a relatively lonely Republican critic of the congressman from Iowa.

King is still the co-chair of the reelection campaign for Iowa Republican Governor Kim Reynolds, and the Des Moines Register felt it necessary on Wednesday to editorialize under the headline: “GOP can’t keep shrugging as Rep. Steve King, President Trump pander to white nationalists.”

This week, a pair of Iowa Jewish community leaders—Alan Steckman, the president of Adas Israel Congregation in Mason City, and John Pleasants, the president of the Ames Jewish Congregation—wrote: “When King promoted white supremacist ideology, many of us we were silent. We will not be silent now. Stand with us in denouncing Steve King and the ideology he promotes.”

It is appropriate and necessary to denounce King rhetorically. But the voters of northwest Iowa have the power to issue the loudest denunciation. King faces an able Democratic challenger in Tuesday’s election, J.D. Scholten. Polls suggest that the Democrat is closing in on the incumbent.

The Sioux City Journal, a conservative Iowa paper that has backed the King in the past, just broke with him to endorse Scholten. Referencing King’s affinity for “intolerant ugliness,” the paper urged voters to retire the Republican. If Iowans make the choice to bend the arc against white nationalism by renouncing Steve King, they will deliver a message that Donald Trump and Republican leaders cannot ignore.