In a small Arab country, text-messaging young people took to the streets of the capital and successfully deposed their oppressor. Their uprising, named after a fragrant tree, raised hopes for a regional “domino effect” — that one Middle Eastern country after another would become democratic, pluralistic and a Western ally against extremism.

So will today’s Jasmine Revolution in Tunisia end up as disappointing as the “Cedar Revolution” of six years ago in Lebanon — a country now set to complete its transformation into a military outpost for Iran?

Lebanon’s political weathervane, Druze leader Walid Jumbalatt, has once again switched camps. Until last year one of the fiercest enemies of the Iran-Syria-Hezbollah axis, he just announced a political alliance with Hezbollah — whose leader, Hassan Nasrallah, will soon name a candidate to replace Prime Minister Saad Hariri, the son of the leader whose 2005 assassination ignited the revolution that successfully pushed Syria out of the country.

The demise of Hariri’s ruling Sunni-Christian-Druze coalition crushes any remaining hope for the Cedar Revolution as harbinger of a more democratic, pluralistic and tolerant Arab world.

So how about Tunisia instead?

We don’t know the direction the Jasmine Revolution will take next: Will an “improved” dictator take over Tunisia, allowing fearful autocrats in Egypt, Libya, Algeria and Jordan to exhale? Will anarchy win the day? Will democracy and pluralism prevail? Or will a branch of the Muslim Brotherhood wind up calling the shots?

After a food merchant set himself on fire a month ago to protest the country’s economic and political oppression, young people armed with Twitter and Facebook took to the streets of Tunis and elsewhere. Soon, the aging president, Zein el-Abedine Ben Ali, fled to Saudi Arabia.

Ben Ali assumed power in 1987, after deposing his former mentor, Habib Bourguiba — who had turned Tunisia into a secular and tolerant country, enforcing such values as women’s rights. No political opposition was allowed, but Tunisia became a close Western ally. Bourguiba even started talking of accommodating Israel, 10 years before Egypt’s Anwar Sadat even dreamed of signing a peace deal.

Political and economic oppression only grew worse under Ben Ali. When Rached Ghannouchi — the fiercely anti-Western, anti-Semitic, misogynist leader of a Muslim Brotherhood offshoot — scored a small electoral victory, he was swiftly exiled.

But now that Ben Ali is out, Ghannoushi’s Islamist Renaissance Party may well wind up leading the country. While party spokesmen say they’d leave the country’s traditions of tolerance intact, Islamists tend to forget such promises once they take power.

Plus, Tunisia will need allies — and under Ghannoushi it would most likely find them in Iran or in the most extreme corners of Sunni Islamism. With such sponsors, it would be hard for any leader to long tolerate such specters as wine-sipping bikini-clad women on Tunisia’s beautiful Mediterranean beaches.

Power across the Arab world is shifting, as sclerotic pro-Western dictators yield to Islamists opponents of pluralism. Why? Historically, the only opposition Arab rulers tolerated was the mosque. More recently, the most powerful organizing force in the region is al Jazeera, the Qatari-owned cable channel that espouses fierce anti-Western Islamist rhetoric.

As Hezbollah takes over in Lebanon, Hamas grows stronger not only in Gaza but also in the West Bank — and similar Islamist groups are gaining power in Algeria, Somalia and Iraq. Can the two biggest prizes, Egypt and Saudi Arabia, be far behind?

Yes, Tunisia may end up a liberal democracy. Its broad middle class is highly educated, and the country has strong traditions of modernity. But so does Lebanon.

Sure, there are stark differences: The sectarianism that plagues Lebanon’s politics, for one, hardly exists in Tunisia. But the similarities are also there.

President Obama’s best bet now is to clearly state his hopes for a real liberal democracy in Tunisia and the rest of the Arab world — and to look for every opportunity to help freedom’s friends and frustrate its foes.

With America’s waning prestige in the region, it isn’t much, but it may help a little in changing the direction that the dominoes fall.