Donald Trump wasted no time using the recent bombing in New York City to rev up his harsh rhetoric against immigrants of Middle Eastern descent. "This is only going to get worse," he told Fox News. "You have to stop them from coming into the country." Never mind that the accused bomber was a naturalized US citizen who had arrived in the US as a young boy, 22 years ago.

After raising the specter of a "cancer from within," Trump also mused that the fight on terror was being hurt by an excessive concern with civil liberties, suggesting that it was outrageous that the apparent bomber got good medical care and would have, as all Americans do, the right to a lawyer.

Trump is hoping — and liberals are fearful — that terrorist attacks will make his personal political appeal stronger. As scholars, we are more interested in the broader effect of terrorist attacks on the public’s tolerance for marginalized minority groups, including Arab Americans. Political tolerance, after all, is the bedrock of any democratic political system.

Many individual studies have found that presenting people with hypothetical scenarios involving terrorist attacks leads them to express less tolerance for minority groups. When primed with frightening scenarios involving attacks, people are also willing to sacrifice freedom for safety. But laboratory studies have limitations, as do surveys of Americans after large attacks, such as 9/11. In the United States, such events have thankfully been rare enough that it is difficult to draw broad conclusions from the resulting responses.

Israel is a long-term case study in the resilience — or not — of tolerance

Israel, however, offers a rich source of information about the effects of terrorism on political attitudes. Israel has suffered persistent and chronic terrorism since its inception in 1948. It remains a democracy — which shows, on one level, that democracies can survive terroristic threats. Yet our research shows that terrorist attacks over a turbulent period in Israel’s history, 1980 to 2011, exacted a steep price in tolerance. Our work also sheds light on the dynamics that drive that intolerance. Taken together, these findings offer both hope and a cautionary tale for democracies reeling from terrorism.

As any student of democracy knows, attempts to repress freedoms can set in motion a slippery slope that puts democracies at serious risk. But, like clockwork, after terrorist attacks there are calls from some quarters to curtail civil liberties.

One way of studying citizens’ reactions to terrorism has been to ask them about support for specific policies — about their support for torture of suspected attackers, for example, or for aggressive pre-emptive searches that may violate constitutional protections. We took a different approach, looking at how terrorism erodes support for political tolerance of disliked groups in Israel. We think that’s a more direct measure of an important prerequisite of a democracy: the protection of the political freedoms of minority populations.

Survey participants could pick their "least liked" group

We drew on a series of surveys, spanning that 1980 to 2011 period. Participants in the survey were allowed to choose for themselves the group that they disliked the most (a common tactic in so-called "least-liked" studies). Groups singled out by participants often included Arab Israeli political parties, leftist Jewish groups, or pro-Palestinian organizations.

The surveyed Israelis were then asked, on a scale of 0 to 8, whether they would allow members of the group they selected to give a speech on TV, or to demonstrate in public. (We focused on the responses of Israeli Jews alone, because some of the surveys included only Jews, and also because tolerance by the Jewish majority of the Arab minority is a highly salient issue in Israel.)

We then examined how the survey data interacted with separate data about terror attacks. During this period Israel experienced roughly 50 attacks per year , with the rate spiking during the first and second intifadas (1987 to 1993, then 2000 to 2005).

Israelis’ resilience in the face of terrorism is well known. Twenty-four hours after a nightclub or restaurant is attacked, Israelis are back in the same location to demonstrate their resolve not to live in fear. However, our research suggests that persistent tacks do chip away at tolerance of disliked groups. Escalations of attacks — and particularly extended escalations, such as the intifadas — seriously diminished Israelis’ political tolerance. By contrast, the relative dearth of attacks during the Oslo peace process helped raise tolerance to its highest level over the 30 years of our study.

We also looked at the persistence of the decline in tolerance for despised groups, analyzing survey responses three months, six months, and 12 months after an attack. Tolerance did rebound, but not completely: 60 percent of the effect identified at the three-month mark was gone at 12 months.

Is everyone’s tolerance affected by attacks, or just some people’s?

We were also interested in testing two different theories about intolerance. Do terrorist attacks shift voters in general to less tolerant positions? Or does the move toward intolerance occur mostly on the right wing, where hawkish and nationalist rhetoric is more prevalent?

We called these competing hypotheses "Rightward shift" and "Right-wing intolerance." The latter proved to better describe what we saw in the data. Consistently, across the 30 years of our study, the erosion of tolerance precipitated by terrorism occurred mainly among Jews who identify with the right, not the left or the center. When terrorist attacks increased, right-wingers were much less willing to allow political groups they don’t like to give a speech or demonstrate.

In contrast, left-wing Israelis did not display any decrease in tolerance. (There was some evidence of an increase in tolerance, but it was not statistically significant. It’s possible that blatant instances of intolerance and hatred provoked left-leaning citizens to reassert their commitment to freedom and difference when their values are threatened.) The Israelis who identified themselves as centrist declined in tolerance, but not as sharply as the right-wingers.

We also found terrorism had a stronger impact in pushing right-wingers toward intolerance over time. During the Oslo period (1994 to 2000), which saw relatively low levels of terrorism, political tolerance was at its highest level for both the left and the right. But with the attacks of the second intifada in 2001, right-wingers quickly reverted to their low levels of tolerance before the Oslo period, while Jews on the left maintained their support for tolerance in the face of increased attacks.

One reason terrorism pushes right-wingers toward intolerance is that they are following the clear lead of Israeli politicians on the right. When parties on the right "own" the issues of national security and terrorism, as they do in Israel and the US, there exist clear incentives for right-wing politicians to stoke fears of terrorism for political gain.

Right-bloc politicians in Israel regularly accuse Arab citizens of Israel, who constitute 20 percent of the country’s population, of being a "Fifth column" of subversive citizens despite the lack of evidence for such claims. They have also pushed for policies designed to limit the political rights of Israeli Arab parties.

Israel's recent history illustrates how two pillars of democracy — minority rights and political tolerance — can crumble when the extreme right is in power. Benjamin Netanyahu, the leader of Israel’s Likud Party and prime minister since 2009, recently helped pass legislation that allows the Knesset to remove members if a large majority of other members approves, all without judicial review. The law was instantly condemned by the Arab parties at which it was clearly directed.

Yet threatening and limiting the rights of Israel’s Arab citizens has not made Israel safer. It has only managed to stigmatize and alienate both Israeli Arabs and leftist Jews. Nonetheless, our research suggests that continued attacks could tip the balance even further toward Netanyahu and intolerance. Likewise, in the United States, further attacks could undermine citizens’ commitment to civil liberties — and make figures like Trump more appealing.

Citizens take cues on tolerance from leaders

The degree to which minority rights and civil liberties contract after terrorist attacks depends very much on the role of political leaders. How they signal to the public dictates how the country should respond. The clear lesson here for Western democracies is to balance freedoms and security without succumbing to the inflammatory fear-mongering of right-wing candidates like Marine Le Pen of France or Donald Trump.

Le Pen, leader of France’s far-right National Front Party, has called for stripping activist Muslims of their French citizenship and closing mosques. Trump has proposed banning all Muslims from entering the US and implied that American Muslims were to blame for failing to "turn in the people who they know are bad."

Contrast Trump’s inflammatory response to President George W. Bush’s visit to a mosque just six days after 9/11, where he admonished Americans not to harass Arab Americans and Muslims and to respect Islam. ("Islam is peace," he stressed.) "In our anger and emotion," Bush said, "our fellow Americans must treat each other with respect … Those who feel like they can intimidate our fellow citizens to take out their anger don't represent the best of America, they represent the worst of humankind, and they should be ashamed of that kind of behavior."

As Samuel Stouffer, pioneer in the study of political tolerance, argued at the height of the McCarthy "Red Scare" era, political tolerance requires citizens and leaders to deny the impulse to repress domestic groups they dislike by taking a "sober second thought," reflecting on the overriding importance of democratic freedoms. It is precisely when we are under stress that we are to take that sober second thought. That’s when we need to assert the right of terrorist suspects to receive a fair trial, and when we need respect the freedoms of all Americans, regardless of religious affiliations. As history shows, the sober, democratic choice is also the smart choice.

Mark Peffley is a professor of political science at the University of Kentucky. Marc L. Hutchison is associate professor of political science at the University of Rhode Island. Michal Shamir is professor of political science at Tel Aviv University.

The Big Idea is Vox’s home for smart, scholarly excursions into the most important issues and ideas in politics, science, and culture — often by outside contributors. If you have an idea for a piece, pitch us at thebigidea@vox.com.