The desperate refugees setting sail on rickety boats and scaling barbed-wire fences to enter the European Union come predominantly from Syria. This crisis won't end soon, because the Syrian conflict isn't going to end soon.

The Europeans can't solve it on their own. So it's time for the United States to provide leadership - by pressing our rich Gulf Arab allies to do much more for the refugees and by doing more ourselves.

That is not just a moral imperative. It makes national security sense.

The refugee crisis has been primed to explode for the past three years. It took the photo of the lifeless body of 3-year-old Aylan Kurdi to galvanize global sympathy in a disaster that aid agencies have long warned about.

The image of sea water lapping against Kurdi's tiny corpse impelled Chancellor Angela Merkel to open Germany's gates further and agree to accept 800,000 refugees and migrants this year.

But Merkel's generosity can't cope with the enormity of the problem. "What Germany has done is extraordinary, but clearly one is going to be overwhelmed if one does this," says the University of Oklahoma's Joshua Landis, a leading expert on Syria. Many other European nations are refusing to endorse a plan to require all EU members to resettle a fair share of asylum seekers.

Right-wing parties in Europe are whipping up opposition to a "Muslim invasion," although this wave of Syrians is mainly professionals, artisans, students, and small-business people, often secular in their lifestyles. They have much to offer European states where birthrates are low.

"These are ideal immigrants," says Landis, "middle-class people who still have enough money to pay smugglers." Many come from government-controlled areas where they were spared the worst of the war, but are now trying to flee as the Syrian state is collapsing.

Yet with anti-immigrant sentiment rising, Germany has reintroduced border controls, followed by other European countries. "America is building a giant wall with Mexico," says Landis, "and we built a much better Coast Guard in order to keep Haitian boat people out. I presume that's what Europe will do."

Clearly Europe can't absorb all those fleeing Afghanistan or failed states in Africa. But keeping refugees from war-torn Syria out may create bigger problems than letting them in.

Over the past four years, the Syrian exodus has created a lost generation of youths without education or prospects. In May, I visited the desolate Zaatari refugee camp in Jordan, where 100,000 Syrians live in trailers on terrain that looks like a moonscape. The men have no work, and thousands of teenage boys no schooling or hope.

Their anger may well drive many to return home and join jihadi militias.

Millions of Syrian refugees threaten to destabilize neighboring countries. Tiny Lebanon has taken in 1.13 million Syrians, who now make up a fourth of its population. Jordan, where unemployment is high and services strained, has accepted 629,000. Turkey, although wealthier, is straining to cope with 1.8 million.

As Syria crumbles further, additional millions may flee.

The best solution would be a negotiated end to the conflict. Some hope the nuclear deal with Iran will enable Washington to work out a solution with Tehran and Moscow, the main supporters of Syrian dictator Bashar al-Assad. For the foreseeable future, that is a pipe dream.

So is the fantasy of creating safe zones for refugees along the Syrian-Turkish border. No one has explained whose troops would protect those zones from Syrian shelling or provide safe haven for civilians amid wrecked towns and villages.

Which leaves this question: If Europe is overwhelmed by the Syrian refugee challenge, who else can step up?

Here is where President Obama (finally) has to get active. The United States leads the world in humanitarian aid to Syrian refugees over the past four years (around $4 billion) but has admitted only 1,200 refugees. The president has now pledged to allow in a paltry 10,000 more over the next year, but our dysfunctional system of security checks will take at least two years to clear them.

This is nuts.

Obama bears substantial responsibility for the Syria mess, having failed to help Syrian moderates when they still existed. He subcontracted the job of helping Syrian rebels to Gulf Arab states that preferred Islamist militias. Those same Gulf Arabs - with the exception of the United Arab Emirates - have done far too little to assist the refugees they helped create.

So the president must press Gulf Arab leaders to ramp up humanitarian aid (so far only a fourth of what Washington has provided). If the Saudis offered to pay refugee resettlement costs in Europe, more countries might allow Syrians to enter.

And Obama should urge Gulf states to invite many more Syrians in, not to sit in desert refugee camps, but to work and live. After all, 25 years ago, hundreds of thousands of Kuwaitis were given refuge in the Gulf after the invasion of their country by Saddam Hussein.

To set an example, Obama should invite 100,000 Syrians to settle here, just as Cubans were welcomed, or Vietnamese after the end of the Vietnam war. It would be shameful and shortsighted to do any less.