Presidents from both major parties have led America in waging a 15-year "war on terror." Both George W. Bush and Barack Obama acted for the nation as best they knew how. Neither was able to unite his country.

We have twisted ourselves into a knot that cannot be untied by each partisan side pulling its own rope harder. The debate we need now cannot be understood in partisan terms or captured in a slogan — "Bush lied, people died"; "Obama's a wimp."

Each president has uncovered truths about the nature of our struggle. Each has struck blows against our enemies. The next president will not be called to vindicate or repudiate Obama or Bush. The next president will be called to carry the torch forward.

Failure is likely if our foreign-policy debate is reduced to a clash of cartoon histories of these last 15 years — each with its villain in the person of the opposing party's president. We must stop fomenting hatred against our presidents. Hatred distorts our perception of reality and blinds us to the good others have done. It poisons our national life and destroys the presidency as an office around which the whole country can rally.

We must hope the next president, whoever it is, will benefit from a clarified strategy worked out in congressional debates and informed by serious journalism and scholarship into the religious, national and military realities that define our present predicament. We need leaders thoughtful enough to rethink and realign our strategy and our alliances with the true contours of a worldwide conflict.

Let us review what we know for sure. On Sept. 11, 2001, men willing to die for a religion attacked us — not for the first time. They fought for no nation. They saw Christian nations, especially America, as their enemies. They saw the Jewish state as their enemy. They saw post-communist, orthodox Russia as their enemy. They even saw most Arab and Muslim states as their enemies.

Yet they came from countries that had supported religious schools where they had learned a purified brand of Sunni Islam. Of the 19 hijackers, 15 were from Saudi Arabia. The Taliban then governing Afghanistan, which had harbored the 9/11 terrorists' Al-Qaida army, had been trained in the same religious ideas — in Pakistan.

After the Taliban fighters were evicted from Afghanistan, they found refuge in Pakistan. When Osama bin Laden, chief of Al-Qaida, was finally found and killed a decade later, he was living quietly in a Pakistani city — Abbottabad — his compound less than a mile from Pakistan's most prestigious military academy.

The power-couple terrorists in San Bernardino, Calif., last December were true believers in this same "reformation" movement within the Sunni branch of Islam, which preaches a return to a purer, ancient form of fighting Islam. It is protected and nourished under its different forms in Saudi Arabia and Pakistan. Its believers are sometimes called "Salafists" ("salaf" means ancestors) and sometimes "Wahhabis" (Muhammad Abd-al-Wahhab was the 18th-century founder of the Arabic branch of this movement). Salafist Sunnis have carried out almost every significant anti-U.S. terrorist act.

This is the religion of Saudi Arabia, and of Osama bin Laden, raised in one of Saudi Arabia's wealthiest families. The Taliban, which gave Bin Laden and his killers shelter in Afghanistan, had its source in a Salafist school that arose first in Deoband, India. The Deobandi students (Taliban means students) are South Asia's Wahhabis.

Only three of the world's countries recognized the Taliban as a legitimate government while they were hosting Bin Laden and Al-Qaida. They were Saudi Arabia, the United Arab Emirates ­— and Pakistan.

In short, an honest debate of American policy in the war on terror must address this riddle: Why are two of our most trusted "allies" all these years — Saudi Arabia and Pakistan — also the primary guardians of our deadliest enemies?

Old friends and new

As our foes come into sharper focus, so, too, might potential allies.

After the 9/11 attacks, two major Mideast figures personified opposition to the U.S. — Bin Laden and Saddam Hussein. Our presidents took them both out.

Deposing Saddam in 2003 revealed a religious fault line that years of battle have only deepened. We had deposed a tyrant and freed a Shia majority in Iraq eager to exercise self-rule. The fury of the Salafist Sunni world against this — demonstrated in the 2006 Al-Askari Mosque bombing in Iraq and repeated in bombings of Shia mosques from Pakistan to Yemen to Kuwait — revealed a hostility to the Shia that we are only now grasping as fundamental to the nature of our conflict.

It turns out that the Salafist Sunni movement to purify Islam considers the Shia as the first corrupters of the ancestors' faith. The Shiites are "the lurking snake, the crafty and malicious scorpion," said Abu Musab al-Zarqawi, who turned much of the attention of Al-Qaida and subsequently the Islamic State in Iraq and the Levant to fighting the near enemy (the Shiites) before the far enemy (the Americans).

The creation of ISIL in the Sunni lands between two Shia governments — Iraq and Bashar Assad's Syria — was a testament to Al-Zarqawi's strategic foresight. He was killed in 2006, but his strategy goes on. The present head of ISIL, Abu Bakr al-Baghdadi, has continued this strategy, telling his followers to put their swords "first of all to the Rafida [a pejorative term for Shiites] wherever you find them."

Why has it taken us so long to see that the Shiites have been the primary victims of Salafist terror? It goes back to November 1979, when a Shiite-inspired popular revolt overthrew the Shah of Iran and held some 60 American hostages for more than a year. The shah was a pivotal ally of both Israel and the U.S., and the conflict between our nations has persisted for almost four decades.

Despite this, President Obama came to office promising to talk without preconditions to Iran and Syria (and North Korea), proposing diplomacy rather than "regime change." This has afforded the U.S. an opportunity to do what Nixon did with China — to realign allies and enemies in a larger struggle.

The Obama strategy of stepping back from military action and stepping forward with diplomacy could leave the next president much more freedom in both the Mideast and South Asian theaters. They are very different situations, but in both Obama has made it possible to reconfigure our alliances to more effectively isolate our enemies — including the potential for a dramatic new relationship with India and a much-needed reassessment of our deadly 50-year embrace with Pakistan.

We need members of Congress in both parties to recognize Obama's maneuvers as creating an opportunity to think anew, not least about this: Iran is the sworn enemy of Saudi Arabia. India is the sworn enemy of Pakistan. A sober re-evaluation of our Saudi and Pakistani allies will open the chance for powerful new alliances with India and Iran.

This war also makes potential allies of two other enormous nations that were America's blood brothers in World War II but afterward were turned against us by their thraldom to atheistic communism. Russia and China gave many more lives than we did in our common fight against Nazi Germany and Imperial Japan.

These giant regional powers are now being cast as rising rivals inexorably destined to be our future foes in the zero-sum game of foreign-policy "realism." But in this fight against terror, and in peaceful endeavors ahead, strong regional actors could be strong regional friends. They should be our allies.

We have reconciled with our old enemies — the Germans and Japanese. Surely we can reconcile with our old friends.

The right religious war

Presidents Bush and Obama have both properly resisted efforts to cast this war as "America vs. Islam." But neither administration has been religiously fluent enough to explain that we are, all the same, in a religious war — specifically against Salafist Sunnis.

In the Islamic world, this binds us with the Shia Muslims who are being persecuted for their religion by the Salafist zealots. More than Christians, more than Jews, the Muslim Shia are victims of religious persecution. The air war against the Shia population of Yemen is the most-violent and least-reported killing front in our present conflict. Christians under siege rightfully call for special refugee status and protection in this war. And wherever the Shia are a minority, they have the same religious claim.

In some ways, our policies should discriminate on the basis of religion — because one form of Islam is trying to kill us, while other forms are willing to abide us, and still others are eager to join us in making the peace. It does Muslims as a group no good to "treat them all the same."

Religious discrimination sounds un-American. But when religion explicitly becomes a motive for warmaking, it is hardly a crime against tolerance to protect the victims and assail their persecutors. It was the Jews of Germany, not the Lutherans, who needed refuge in the 1930s.

All Muslims do not look alike. U.S. policymakers since Republican Secretaries of State Donald Rumsfeld and Condoleezza Rice have obscured this central fact, implying that both sides, with their retro religious thinking, were equally at fault for what was shrugged off as "sectarian violence." That thinking portrayed the armed defense by Shia from religious genocide as sectarianism. It was implied that peace would follow if only Iraqi Muslims would grow up, get over their superstitions and became sensible secularists with lots more female officeholders. U.S. foreign-policy "experts" understood American feminism; it was Islam and Iraq that befuddled them.

Wherever Salafist Sunnis dominate, the Shia are persecuted for religious reasons. If our overly secularized State Department cannot see that, we can hope Christian activists will start naming the beast. We will soon see the Shia of Hezbollah and the Maronite Christians of Lebanon under attack by radicalized Syrian Sunnis. Lebanon will be the next place where religious literacy must inform our alignments.

Toward a new alignment

Finally, we must once again relate to Israel as our ally, not an outsourced State Department. Israel's prime minister is our friend, not our speaker of the House. Allies are often most helpful when they serve as a corrective by disagreeing with a friend's shortsighted or wrongheaded policy. In 1957, the Eisenhower administration opposed the Israelis in their alliance with imperial powers Britain and France against nationalist Egypt. Yet, we remained allies.

Today the ruling party in Israel has partnered with the most reactionary regime in the region — an ever-narrowing subset of the royal family of Saudi Arabia. The alliance is sealed by mutual hatred of Iran. We must help Israel escape this fatal embrace.

The link of Wahhabi Sunnis and secular Israelis against the Shiite Persians is built on hatred alone. The new Saudi ruler and his son, the deputy crown prince, are centralizing authority in their branch of the royal clan. To counter the hostility from all their cousins who want to rule, they are solidifying their support among the clerics. The world shudders, but the most radical Wahhabi elements in the kingdom are ecstatic over the bombing of Shiites in Yemen and the execution of Shia cleric Nimr al-Nimr. It's all in a day's work in the movement to purify Islam — the Salafist way.

We need to give our ally Israel space to escape this death clasp so it can openly join a larger coalition respecting the religious character of Shia states as well as the Jewish state. Russia, China and India will join us. In the short term, it may seem we are against Israel because we refuse to adopt the "every Shia is an Iranian" line of the Salafists. But we must build the new alliance, then welcome Israel as it severs ties with the Wahhabis. We must lead from the front this time.

Let us thank our president for being courageous enough to pull us back from rash military actions that would have precluded new strategic alliances. Let us thank Donald Trump for pushing political leaders and the media at least a little toward recognizing the reality that we are a nation at war with a religion — albeit a specific branch of a religion.

To fight this religious-political war, we need to call upon our own civic brotherhood under God. As before, we must transcend affinities of party and color and renew deeper loyalties that bind us. We must stop hating one another so we can have a good argument about how to face our common danger. The momentous changes our foreign policy now requires are drama enough — no need to shout.

David Pence, of Mankato, is a retired physician and teacher. He writes about religion, politics and men at Anthropology of Accord.