Frederic Saliba writes: The lake at Xohilmilco is the setting of chinampas, the floating vegetable gardens developed here more than 500 years ago. They are one of the last remaining features of the ancient Aztec capital of Mexico-Tenochtitlán, conquered by Spaniards in 1521.

Five centuries on, this network of waterways and artificial islands, a UNESCO World Heritage Site, is threatened by the city’s disorderly expansion and over-exploitation of its water resources. The government of Mexico City has an action plan, financed by France, to save this enormous district of the capital that is also the home of ancestral farming traditions and exceptional biodiversity.

“There is no time to lose,” says resident Claudia Zenteno, pointing with clear frustration at plastic bottles, bags and cans floating in the dark, stagnant water outside her house.

Zenteno, a 50-year-old former accountant turned environmentalist, lives by the lake, in a part removed from the piers and boat tours where the water is regularly cleaned for the 1.2 million tourists who visit every year. “We used to have a wonderful view when we arrived here in 1995,” she says. “It’s a shantytown today.”   Can Mexico’s Floating Gardens Survive

Hans-Werner Sinn writes: Game theorists know that a Plan A is never enough. One must also develop and put forward a credible Plan B – the implied threat that drives forward negotiations on Plan A. Greece’s finance minister, Yanis Varoufakis, knows this very well. As the Greek government’s anointed “heavy,” he is working Plan B (a potential exit from the eurozone), while Prime Minister Alexis Tsipras makes himself available for Plan A (an extension on Greece’s loan agreement, and a renegotiation of the terms of its bailout). In a sense, they are playing the classic game of “good cop/bad cop” – and, so far, to great effect.

Plan B comprises two key elements. First, there is simple provocation, aimed at riling up Greek citizens and thus escalating tensions between the country and its creditors. Greece’s citizens must believe that they are escaping grave injustice if they are to continue to trust their government during the difficult period that would follow an exit from the eurozone.

Second, the Greek government is driving up the costs of Plan B for the other side, by allowing capital flight by its citizens. If it so chose, the government could contain this trend with a more conciliatory approach, or stop it outright with the introduction of capital controls.

Other eurozone central banks are forced to create new money to fulfill the payment orders for the Greek citizens, effectively giving the Greek central bank an overdraft credit, as measured by the so-called TARGET liabilities. In January and February, Greece’s TARGET debts increased by almost €1 billion ($1.1 billion) per day, owing to capital flight by Greek citizens and foreign investors. At the end of April, those debts amounted to €99 billion.

A Greek exit would not damage the accounts that its citizens have set up in other eurozone countries – let alone cause Greeks to lose the assets they have purchased with those accounts.  A similar situation arises when Greek citizens withdraw cash from their accounts and hoard it in suitcases or take it abroad.

The ECB bears considerable responsibility for this situation. By failing to produce the two-thirds majority in the ECB Council needed to limit the Greek central bank’s self-serving strategy, it has allowed the creation of more than €80 billion in emergency liquidity, which exceeds the Greek central bank’s €41 billion in recoverable assets.

If the ECB finally removes Greece’s liquidity safety net, the Greek government would be forced to start negotiating seriously, because waiting would no longer do it any good. But, with the stock of money sent abroad and held in cash having already ballooned to 79% of GDP, its position would remain very strong.

In other words, thanks largely to the ECB, the Greek government would be able to secure a far more favorable outcome – including increased financial assistance and reduced reform requirements – than it could have gained at any point in the past.

Philip Smyth writes:  Both rebel forces and the Islamic State are on the march in Syria. Islamist opposition groups have advanced in the south near Daraa and in the north in Idlib; the Islamic State, meanwhile, last week
conquered the central city of Palmyra. President Bashar al-Assad’s regime is clearly under strain, but rumors of its impending demise are greatly overstated.

While Assad and his Iranian allies are increasingly struggling to field enough forces to protect strategically important areas, they have nonetheless moved aggressively to prevent regime collapse. Using cash and
coercion, Assad has launched new efforts to bolster troop levels and engender further loyalty. Just last week, the Syrian regime announced its hope for a $1 billion credit line from Tehran to continue the fight.
More importantly, Iranian-backed foreign-fighter recruitment and deployment have increased dramatically. With these efforts, the wheels are now in motion for the regime not only to contain rebel advances, but also to push them back.
Early in 2014, the deployment of pro-Assad foreign fighters hit a significant snag when thousands of Iraqi
Shiite militiamen started returning to Iraq following the Islamic State’s gains there. However, the crown jewel of Iran’s proxy network — the Lebanese paramilitary group Hezbollah — soon picked up the slack for
the redeployed Iraqis. Hezbollah recruitment has increased, both within Lebanon and via the group’s affiliated proxies in Syria. The organization also boosted its influence by targeting not just Shiite Muslims
for recruitment, but also other minorities, such as Druze and Christian groups, forming them into paramilitary organizations fitting the Hezbollah model.

Roping off the Middle East and letting them solve their own problems sounds like a good idea, but simply won’t work.  President Obama is facing the problem head on.  Here is an interview by Jeffrey Goldberg in which the President describes his plans and hopes.

Tensions between the U.S. and the Gulf states, I came to see, have not entirely dissipated. Obama was adamant on Tuesday that America’s Arab allies must do more to defend their own interests, but he has also spent much of the past month trying to reassure Saudi Arabia, the linchpin state of the Arab Gulf and one of America’s closest Arab allies, that the U.S. will protect it from Iran. One thing he does not want Saudi Arabia to do is to build a nuclear infrastructure to match the infrastructure Iran will be allowed to keep in place as part of its agreement with the great powers. “Their covert—presumably—pursuit of a nuclear program would greatly strain the relationship they’ve got with the United States,” Obama said of the Saudis.

In the wake of what seemed to have been a near meltdown in the relationship between the United States and Israel, Obama talked about what he called his love for the Jewish state; his frustrations with it when it fails to live up to both Jewish and universal values; and his hope that, one day soon, its leaders, including and especially its prime minister, will come to understand Israel’s stark choices as he understands Israel’s stark choices. And, just as he did with Saudi Arabia, Obama issued a warning to Israel: If it proves unwilling to live up to its values—in this case, he made specific mention of Netanyahu’s seemingly flawed understanding of the role Israel’s Arab citizens play in its democratic order—the consequences could be profound.   Obama and the Middle East