CAIRO, EGYPT — The Syrian regime's reputation, along with that of Shia allies Hezbollah and Iran, is being tarnished here in the Middle East. Sure, Westerners have long seen these groups as villainous. But their militant opposition to Israel over the past few decades has made them heroes in the eyes of many Muslims. But now, as Bashar al-Assad's brutal crackdown on his own Sunni Arab citizens reaches nightmarish proportions, the Shia coalition has found itself on the wrong side of public opinion in the Middle East.

Across the region, walls have long been scrawled with messages in support of Palestinians and condemning Israel. From Yemen to Morocco, few issues energize and unite Arabs across the social spectrum like opposition to Zionism. I often meet Tunisians and Egyptians who are more knowledgeable and passionate about politics in the occupied territories then they are about the situation in their home countries.

These days, however, Palestine is facing stiff competition in the sympathy department.

Since the start of of the Syrian civil war, an estimated 93,000 people have been killed. The conflict, which started out as optimistic and peaceful protests calling for democracy, has transformed into a brutal sectarian war, pitting the Sunni Muslim majority against members of Assad's dominant Alawi community, a heterodox strain of Shia Islam.

The conflict has already taken on a regional dimension, with foreign Sunni and Shia fighters flooding into Syria from across the world to take part in what is increasingly being called a jihad by both sides. Shia powers like Hezbollah and Iran have thrown their unconditional support behind the regime, while Sunnis from the pro-Western Gulf Emirs to al Qaeda are providing support to the opposition.

The streets of Cairo (where nearly all the Muslims are Sunni) are still full of Palestinian flags and graffiti condemning Israel, but they are also being supplanted by the three-starred flag of the Free Syrian Army and graffiti stencils portraying Assad as Hitler.

Conflict between Shia and Sunnis, and even the hateful rhetoric being used, is nothing new. It has its origin in a succession dispute that occurred after the Prophet Muhammad's death, and has always had more of a political flavor than a theological one. Sunni Muslims are the majority, and over the centuries Shia Islam tended to be taken up by ambitious rulers who wanted to shake off the influence of whatever faction was dominating Sunni Islam.

In the 16th century, a dynasty of Persian-speaking Iranians, the Savafids, forcibly converted their people en masse to Shia Islam as part of a holistic effort to free themselves from the domination of Sunni Arabs and Turks. Since then, generally speaking, Shia Muslims regardless of ethnicity have tended to ally themselves with whatever regime is dominant in Iran.

When Shia clerics seized control of Iran's government in the late 1970s, they established and armed Shia militias wherever they could across the Arab world, and pushed these groups to confront Israel and pro-Western Sunni monarchs. The most powerful Shia militia, Hezbollah in Lebanon, became an important regional actor in its own right. The Alawi regime in Syria, despite being nominally secular, eagerly joined the Iranian coalition.

The Israeli conflict was perfect for Iran and its Syrian allies. Emphasizing the purported Jewish threat took attention off the fact that the Shia regimes were out of step with the religious consensus and often committed human rights abuses that equaled or dwarfed Israeli atrocities.

By the early '80s, most Sunni Arab governments were beginning to normalize relations with Israel. This was massively unpopular with the Sunni Arab public, who began to see Iran, Syria, and Hezbollah as the most credible defenders of Arab and Muslim dignity.

As a Sunni Tunisian friend put it a few years ago, "Hezbollah is wrong about religion, but we respect them because they stand up to Israel."

Hezbollah, and by extension Syria and Iran, scored a tie against Israel in the 2006 border war. For a Muslim public long demoralized by Israel's apparent invincibility, this was as good as a victory. Assad's regime and the Iranians, who provide the lion share of support for Hezbollah, used this new credibility to shore up their position in the region.

But today, whatever goodwill the Shia coalition had on the streets of Cairo and elsewhere has evaporated. The Syrian regime has caused most of the deaths in this war. Hezbollah, desperate to keep its allies in power, have joined in the fight, sending warriors trained to fight the IDF to kill Sunni revolutionaries.

While Iran and their militant Shia allies are certainly losers in this situation, it's hard to say if any winners will appear out of the Syrian tragedy. Violence has already spilled into Turkey and Lebanon, and tensions have reverberated throughout the region.

Israel seems happy to watch from the sidelines as two groups of Muslims tear each other to pieces, but they have more to fear than anyone from the the increasing regional chaos.

 America, which lost all of its will to fight and most of its credibility in the region during the disastrous Bush years, has been forced to sit back and watch as Assad uses chemical weapons, and both sides become increasingly radical, genocidal, and anti-Western. Yes, the U.S. is now going to arm the Syrian rebels, but there is clearly very little appetite in America for real intervention.

The Sunni princelings of Saudi Arabia and the Gulf states seem to have the most to gain from the war and have been supporting a wide range of Sunni militias, from the relatively moderate Free Syrian Army to al Qaeda-affiliated groups. The Sunni monarchies base their power on a mixture of strict Sunni Islam and business with the West, and have long feared Shia militancy. While they are taking this opportunity to strike an irreparable blow to their enemies in Iran, the violence doesn't seem like it will end anytime soon and it is still escalating.

In Cairo and across the Arab world, young Sunni men are heeding the call to jihad and flying to Syria to take up arms against Assad. If past conflicts are any indication, many of these men will get martyred, but most will return to their homes across the Arab world traumatized, radicalized, potentially ready to fight the very leaders who financed their adventures in Syria.

As always, the biggest losers are average Syrian people of all ethnicities who simply want to live in peace. Instead, the Syrian people could have decades of death, economic disruption, and refugee camps ahead of them.