The fact that Iran has been prevented from having an atomic bomb is, in itself, a major success. But that this has been achieved through some hard work of diplomatic filigree, and between sworn enemies, makes what was agreed upon in Vienna fulfill all the conditions to be considered a historic success.

The deal, agreed upon by U.S. Secretary of State John Kerry and by Iran's Foreign Affairs Minister Mohammad Javad Zarif, arrives after two years of tense and costly negotiations that intended, on one hand, to neutralize the threat that Iran's suspicious nuclear program would stray from the civil sphere to become military and, on the other hand, to get rid of the harsh sanctions that the West imposed on the ayatollah regime for violating previous commitments.

In this difficult confrontation, Iran wanted it to be believed that its program was aimed at generating electricity. And the West was unwilling to allow Iran to upset the balance, if we can call it that, of the powder keg that is the Middle East, with so many unstable factors.

All in all, the agreement is a reality. Iran is committed to reducing its uranium enrichment program; it will get rid of what it has stored, eliminate any possibility to use plutonium for military purposes and be subjected to close monitoring by the International Atomic Energy Agency (IAEA).

This way, the U.S. and its other allies in this negotiation — the United Kingdom, France, Russia, China and Germany — have agreed to gradually suspend the sanctions drowning the Iranian economy, especially the ones related to the ban on its oil sales and the isolation of financial and commercial circuits. This will be done as the compliances are verified. President Obama stated it clearly: "This deal is not built on trust. It's built on verification."

It is an extraordinary event, with significant hurdles still. Domestically, Obama has to wait for the approval of Congress, dominated by a Republican opposition, a decision over which a threat of a veto hangs in case of a rejection. And, externally, to convince his partners, Israel and Saudi Arabia, that the arrangement with Iran is the lesser evil.

We will have to see if Israel distrusts Tehran's sincerity and believes the deal leaves its capacity to build the bomb intact. Besides, the support that this country gives the movements considered "terrorists," such as Hezbollah in Lebanon and Hamas in Gaza, is a pill that Netanyahu will hardly swallow. But, for Moscow, the agreement opens the possibility to build a vast coalition against the Islamic State group.

In regards to Saudi Arabia, the issue is related to the rivalry with Iran for supremacy in the Muslim world. The former [country] is Sunni and the latter is Shiite; several latent conflicts in the region are related to this dispute, and the nuclear deal strengthens Tehran's position. The least desired scenario is Riyadh creating its own nuclear program. Israel, for its part, has never acknowledged having an atomic bomb.

That being said, Obama's style collects another undeniable triumph. There are many differences between Cuba and Iran, but they have something in common: the victory of classic diplomacy and dialogue with the enemy. This is the great lesson.