Not since the Vietnam War has a foreign-policy issue transformed Western domestic politics in the way the threat from Islamic State has. Neither the attacks of Sept. 11, 2001, nor the subsequent wars in Afghanistan and Iraq — however costly and corrosive of national purpose — so profoundly reset the playing field of politics. Across the West, domestic policy debates — ranging from immigration to law enforcement to education — are now refracted through the lens of the new terrorism. Because of the Islamic State-related attacks in the United States and Europe, the line between foreign and domestic policy is gradually being erased. Distinctions of left vs. right, or liberal vs. conservative now obscure rather than illuminate the policy decisions confronting governments. Today, an anti-immigrant policy can just as easily emerge from the political far left as from the far right. The metastasizing crisis of confidence in mainstream politics may have been sparked by the Islamic State atrocities in Paris, Brussels, Istanbul and San Bernardino, California. But it is rooted in something deeper: a corrupting gulf between the professed values of democracy and civil rights in Western policies, and the reality of the ways national interests in stability and security are pursued, both at home and abroad. Establishment politicians as diverse as former Secretary of State Hillary Clinton, German Chancellor Angela Merkel, British Prime Minister David Cameron and French President Francois Hollande are struggling to manage this peril. Can they hold a center of moderation and pluralism? Or will fringe forces of isolation and exclusion overwhelm a half century of mainstream Western policies? The answer to this challenge is a new conditionality in both foreign and domestic policy. Abroad, this requires a new basis for alliances in which economic and military support is dependent on a common commitment to the values of modernity — and not just an interest in stability. At home, this means crafting a new compact between native and immigrant communities, with a promise of equality of citizenship going hand in hand with acceptance of pluralism and gender equality as the bedrock of free societies. For the past half century, Western policy in the Middle East has been straining under the weight of its own contradictions: stability vs. democracy; oil dependency vs. wider economic development; military intervention vs. non-interference. If today there is a major Middle East government acting in ways other than deeply inimical to Western interests, as well as values, it is doing so by stealth. A parade of policies emanating from Riyadh, Tehran, Baghdad, Cairo, and Damascus are stoking sectarianism, inflaming radicalism, increasing the risk of regional armed conflict, destroying development and setting back human rights. But merely acknowledging this — even as openly as President Barack Obama did in a recent Atlantic interview — without altering Western policy will do nothing to change this dynamic between the West and the Middle East. Worse, it can only widen the popular distrust of government emanating from the gap between the West’s professed values of democracy and civil rights, and their relative absence from much of its foreign policy. Now, the reality of US energy independence and the threat of a new global scourge of jihadism present a unique opportunity to challenge the half-century-long bargain between Western and Middle Eastern regimes. In the age of Islamic State, the reality for Western nations is that securing the stability of Middle East regimes matters less, and the West’s own national security matters more. Today, Western support for Middle East governments can be conditioned — in reality and not just rhetoric — on the degree to which their actions align with Western values and interests. Critically, however, what will distinguish the solutions of centrist politicians like Clinton from the slogans of fringe leaders like GOP front-runner Donald Trump is a recognition that within each of these Middle Eastern countries are genuinely innovative forces of reform. Today, Western governments often encourage these forces of modernity with words, but still support the region’s reactionary governments with weapons and funds. The new conditionality would turn this decades-long approach on its head. If Middle East regimes embrace their own vibrant agents of reform among the young and often women activists and leaders — rather than imprison, torture or delegitimize them — they can continue to rely on Western political, security and economic support. If not, they can look elsewhere for allies. Aligning values and interests in foreign policy will, however, only address half the hypocrisy undermining traditional politics in the West today. In domestic policy, too, a dangerous gap has opened up between the values underlying Western modernity and their violation among certain marginalized immigrant communities. Within European and US societies, the rising tide of intolerance toward refugees and migrants betrays fundamental Western values. However, another equally dangerous betrayal of values is the indulgence of reactionary, occasionally extremist, practices of religious intolerance within many immigrant communities. This policy has undermined domestic security in troubled suburbs from Paris to Brussels to Copenhagen and constitutes a fateful abdication of modernity’s values by centrist politicians, which has left their ostensible defense too often in the hands of bigots, reactionaries and xenophobic populists. To confront their surging support, mainstream leaders have to recognize that standing up for pluralism has two aspects to it. If upholding liberal values means defending a Muslim woman’s right to wear a head scarf to work, it must also mean defending her right to education, equality and a free choice in her life decisions. Instead, European government policies have often left the brave and embattled agents of modernity within immigrant communities caught in a vicious vise between two exclusionary forces of native and immigrant intolerance. Upholding the values of pluralism against the forces of exclusion within both communities is the surest path to securing the interest in development and human dignity. Divorcing the values of modernity from the design of foreign and domestic policies in an age of migration and jihadist terror serves only to undermine economic stability and domestic security. Ultimately, aligning values with interests will get the West not just the right policies, but the right politics. Nader Mousavizadeh is co-founder of Macro Advisory Partners, and co-author, with former United Nations Secretary General Kofi Annan, of “Interventions: A Life in War and Peace.”