Yet the real meaning of the nuclear deal has gone largely overlooked: The dominant trend of the early 21st century is the rise of democratic powers to positions of regional and even global influence.

The visit this week to Tehran by Turkish Prime Minister Recep Tayyip Erdogan and Brazilian President Luiz Inacio Lula da Silva was a rare show of personal, high-stakes diplomacy by a pair of world leaders.

"Diplomacy emerged victorious," Brazilian President Luiz Inácio Lula da Silva declared on May 17, after his country and Turkey signed its sketchy nuclear deal with Iran. That was something of a reach. But, if not victorious, diplomacy was taking a rare turn on center stage...

Israeli Prime Minister Benjamin Netanyahu convened top advisers Tuesday to assess an Iranian nuclear deal with Turkey and Brazil that may stall the new U.N. sanctions Israel seeks against Tehran, officials said. The unscheduled inner cabinet meeting, accompanied by an announcement from Netanyahu's office that ministers were under orders to withhold public comment, reflected Israel's worries about the efficacy of foreign efforts to negotiate with Iran.

Two leaders from two big regional powers, Luiz Inácio Lula da Silva of Brazil and Recep Tayyip Erdogan of Turkey, took a risk in traveling to Iran and negotiating over the country's contentious nuclear programme. Many said they would fail.

Brazilian President Luiz Inácio Lula da Silva visits Tehran this weekend in what a US official has called "perhaps the last big shot at engagement" with the Islamic Republic before the UN Security Council applies fresh sanctions against Iran for its refusal to suspend its nuclear program.

South America's largest country, Brazil is keen to play a key role in the whole of the Middle East as it enjoys "traditional" and cultural relations with the countries of the region for several decades.

Among the Summit's outputs were: the Declaration of Brasilia and more than 40 bilateral agreements addressing areas of collaboration including health, education, culture, agricultural development, energy, tourism and civil defense.