Today’s surprise move by Sunni states to close ranks against Qatar has been so well planned that even Maldives joined the effort. Saudi Arabia, the apparent leader of the effort to cut off Qatar, has already acted to make that a physical reality by stopping food shipments over their shared border, and everyone else has stopped flights into the now-isolated nation. The Saudis have now suspended any access to their ports for Qatari-flagged ships, which ups the ante. That doesn’t leave Qatar with many options for food, unless the US is inclined to fly it to them, or if Iran supplies them across the Strait of Hormuz.

The move looks like a squaring off of Sunni interests against Shi’ite expansionism, and pressure on Qatar’s emirate to make a firm choice between the two. But Iran may not be the biggest antagonist in this diplomatic drama, even if they are clearly the long-term target for it:

Even before Monday, Qatar had appeared unperturbed by the growing tensions. On May 27, Qatar’s ruling emir, Tamim bin Hamad Al Thani, called Iranian President Hasan Rouhani to congratulate him on his re-election.

The call was a clear, public rebuttal of Saudi Arabia’s efforts to force Qatar to fall in line against the Shiite-ruled nation, which the Sunni kingdom sees as its No. 1 enemy and a threat to regional stability. Qatar shares a massive offshore gas field with the Islamic Republic.

Qatar is also home to the sprawling al-Udeid Air Base, which is home to the forward headquarters of the U.S. military’s Central Command. It wasn’t clear if the decision would affect American military operations. Central Command officials and the Pentagon did not immediately respond to a request for comment.

Saudi Arabia said it took the decision to cut diplomatic ties due to Qatar’s “embrace of various terrorist and sectarian groups aimed at destabilizing the region” including the Muslim Brotherhood, al-Qaida, the Islamic State of Syria and Iraq (ISIS) group and groups supported by Iran in the kingdom’s restive Eastern Province. Egypt’s Foreign Ministry accused Qatar of taking an “antagonist approach” toward Egypt and said “all attempts to stop it from supporting terrorist groups failed.”

Some of this is simply the age-old enmity between Arabs and Persians, and Sunnis and Shi’a. The catalyst at the moment might be Iran’s attempts to use the breakdown in Iraq to build a land-based line of communication to its Hezbollah proxies in Lebanon, according to Ha’aretz’ Amos Harel:

Intelligence services in Israel and the region are now following events along the Syria-Iraq border.

In both countries, Shi’ite militias, backed by Iran, are moving toward the border. If they can come together on both sides of the frontier and create a band of control, a longtime Iranian aspiration will be fulfilled: to establish a land corridor through which the Iranians can freely move forces, weapons and supplies from Tehran through Iraq to the Assad regime in Syria, and even west of there to Hezbollah in Lebanon.

The creation of this contiguity would follow an achievement chalked up by the Iran-led axis in the region thanks to Russian intervention for the Assad regime in the Syrian civil war. Since the final surrender of the rebel forces in Aleppo in northern Syria last December, the regime and its supporters have slowly expanded their hold on various parts of Syria.

At the same time, the Iranians, through local Shi’ite militias, are helping the United States and Iraqi government fight the Islamic State around the Iraqi city of Mosul. Moving ISIS away from the border lets the Tehran-backed militias  take strategic territory in the desert area west of Mosul near the Syrian border.

That was a likely outcome even without ISIS, or the Syrian civil war, for that matter. A democratic Iraq, with its Shi’ite majority, would eventually become friendlier with Iran and cooperate on security issues. Absent a civil war in Syria, Bashar al-Assad would have provided that land bridge without any potential for interference from the Sunni bloc, or indeed without any cassus belli for intervention. Qatar would have had little to do with this under those conditions.

Today’s events certainly have something to do with this bridge-to-Beirut strategy, but it seems more likely that it has something to do with more pressing issues within the Sunni nations. Recent statements from the emir in support of Hamas and the Muslim Brotherhood appears to have been the final straw — and that comes at a very interesting time, as Ha’aretz also notes:

This exceptional move came after reports of statements attributed to Qatar’s ruler Sheikh Tamim Bin-Hamad, according to which he objected to the hostile attitude adopted by Gulf States and the U.S. against Iran, “a great state that contributes to regional stability”. He also allegedly stated that Hamas, Hezbollah and the Muslim Brothers are not terrorist organizations but resistance movements – also declaring Hamas to be the only legitimate representatives of the Palestinian people.

Qatar later denied that bin-Hamad ever made that statement, and accused the UAE of conspiring with Israelis and Jewish supporters of hacking them as part of the usual conspiracy theories about the Joooooooos. Clearly, the Saudis weren’t buying that explanation, and neither were the other Sunni nations. The timing of the move is interesting, in that it follows after Donald Trump’s visit to the region and demand for progress on the Israeli-Palestinian peace process. By cutting off Qatar, Hamas finds itself weakened even further in its Gaza isolation. At the same time, Hamas’ parent group, the Muslim Brotherhood — now suppressed again in Egypt — also has some of its support cut off. That allows more latitude for Mahmoud Abbas to work with the Israelis and Saudis to regain supremacy in the disputed territories … assuming Abbas is inclined to use it, that is.

If nothing else, this move is clearly understandable from an internal security perspective. Qatar has long been a sort of Casablanca-esque venue, a “wretched hive of villainy” that operates openly among all sides for sotto voce discussions and off-the-books bargains. That has allowed Qatar to play all sides off on each other for a long time, including the US, which has CENTCOM based in the country. Those days may be over, which tells us something about how much the Sunni dictators value Hamas and the Muslim Brotherhood these days. Hamas and its reliance on Qatar and Iran may wind up the biggest long-term loser, although it could take years for them to fully feel the impact of it — assuming that Qatar caves and ejects Hamas and the Muslim Brotherhood, that is.

One interesting question remains: whither Jordan? So far, Amman is keeping mum on this diplomatic isolation.