The Middle East witnessed something radically new two days ago, when the Kingdom of Saudi Arabia responded to a plea by Yemen's president and led a 10-country coalition to intervene in the air and on the ground in the country. "Operation Decisive Storm" prompts many reflections:

Saudi and Egypt in alliance: Half a century ago, Riyadh and Cairo were active in a Yemen war, but then they supported opposing sides, respectively the status-quo forces and the revolutionaries. Their now being allies points to continuity in Saudia along with profound changes in Egypt.

Arabic-speakers getting their act together: Through Israel's early decades, Arabs dreamt of uniting militarily against it but the realities of infighting and rivalries smashed every such hope. Even on the three occasions (1948-49, 1967, 1973) when they did join forces, they did so at cross purposes and ineffectively. How striking, then that finally they should coalesce not against Israel but against Iran. This implicitly points to their understanding that the Islamic Republic of Iran poses a real threat, whereas anti-Zionism amounts to mere indulgence. It also points to panic and the need to take action resulting from a stark American retreat.

Arab leaders have a long history of meeting but not cooperating. From the right: King Hussein of Jordan, Gamal Abdel Nasser of Egypt, Yasir Arafat of the PLO, and Muammar Qaddafi of Libya in September 1970.

Yemen at the center of attention: Yemen played a peripheral role in the Bible, in the rise of Islam, and in modern times; it's never been the focus of world concern – until suddenly now. Yemen resembles other once-marginal countries – the Koreas, Cuba, the Vietnams, Afghanistan – which out of nowhere became the focus of global concern.

The Middle East cold war went hot: The Iranian and Saudi regimes have headed dueling blocs for about a decade. They did combat as the U.S. and Soviet governments once did – via contending ideologies, espionage, aid, trade, and covert action. On March 26, that cold war went hot, where it's likely long to remain.

Can the Saudi-led coalition win? Highly unlikely, as these are rookies taking on Iran's battle-hardened allies in a forbidding terrain.

Islamists dominate: The leaders of both blocs share much: both aspire universally to apply the sacred law of Islam (the Shari'a), both despise infidels, and both turned faith into ideology. Their falling out confirms Islamism as the Middle East's only game, permitting its proponents the luxury to fight each other.

The Turkey-Qatar-Muslim Brotherhood alliance in decline: A third alliance of Sunni revisionists somewhere between the Shi'i revolutionaries and the Sunni status-quotians has been active during recent years in many countries – Iraq, Syria, Egypt, Libya. But now, in part thanks to diplomacy initiated by the brand-new King Salman of Saudi Arabia, its members are gravitating toward their Sunni co-religionists.

King Salman of Saudi Arabia has done something unprecedented in putting together a military coalition.

Isolated Iran: Yes, a belligerent Tehran now boasts of dominating four Arab capitals (Baghdad, Damascus, Beirut, Sana'a) but that's also its problem: abrupt Iranian gains have many in the region (including such previously friendly states as Pakistan and Sudan) fearing Iran.

Sidelining the Arab-Israeli conflict: If the Obama administration and European leaders remain obsessed with Palestinians, seeing them as key to the region, regional players have far more urgent priorities. Not only does Israel hardly concern them but the Jewish state serves as a tacit auxiliary of the Saudi-led bloc. Does this change mark a long-term shift in Arab attitudes toward Israel? Probably not; when the Iran crisis fades, expect attention to return to the Palestinians and Israel, as it always does.

American policy in disarray: Middle East hands rightly scoffed in 2009 when Barack Obama and his fellow naïfs expected that by leaving Iraq, smiling at Tehran, and trying harder at Arab-Israeli negotiations they would fix the region, permitting a "pivot" to East Asia. Instead, the incompetents squatting atop the U.S. government cannot keep up with fast-moving, adverse events, many of its own creation (anarchy in Libya, tensions with traditional allies, a more bellicose Iran).

Impact on a deal with Iran: Although Washington has folded on many positions in negotiations with Iran and done the mullah's regime many favors (for example, not listing it or its Hizbullah ally as terrorist), it drew a line in Yemen, offering the anti-Iran coalition some support. Will Iran's Supreme Leader Ali Khamene'i now stomp out of the talks? Highly unlikely, for the deal offered him is too sweet to turn down.

American diplomats meet again with their Iranian counterparts to capitulate on yet another difference.

In sum, Salman's skilled diplomacy and his readiness to use force in Yemen responds to the deadly combination of Arab anarchy, Iranian aggression, and Obama weakness in a way that will shape the region for years.