Last Saturday, White House officials were boasting about the significance of Saudi Arabia's King Salman bin Abdulaziz Al-Saud's presence at a summit of Gulf leaders at Camp David, Maryland. A few hours later, the king pulled out.
President Barack Obama had been aiming to reassure the Saudis and other Persian Gulf rulers that United States would not abandon its Sunni allies over the looming nuclear deal with Iran.
King Salman's last-minute no-show was not only a sign that President Obama is failing to convince his main allies that his Middle East policies are adequate for tackling a region in grave crisis. It was also part of a pattern of failure that stretches back to the beginning of his tenure as US president.
Mr Obama came to power riding America's anti-war wave, promising a sensible withdrawal of troops from Iraq and Afghanistan. But the pullout from Iraq became a retreat, and there was nothing sensible about it.
Iraq was delivered to Mr Obama in reasonable shape, given what had gone before. The surge had worked and the political situation was manageable. However, in 2011, with Iraq an increasingly safe and secure country and about to take its next step towards becoming an inclusive, stable state, Mr Obama brought the troops home. He did not push Prime Minister Nouri al-Maliki enough to keep a residual force in Iraq, and relied on Mr Maliki's goodwill.
Other nations in the region now want a nuclear deal. The age of proliferation has just begun
We all know what happened next: Mr Maliki, backed by Iran, took up sectarian policies and hunted down Iraqi Sunnis, which contributed significantly to the rise of Islamic State.
Mr Obama had started from a strong position, gave away all his best cards, relied on goodwill of an unreliable man and lost the bet.
Noting Iran's nuclear ambitions, former US president George Bush managed to convince the international community to impose sanctions on the country through the UN Security Council.
Mr Obama maintained the sanctions. However, he consistently lobbied against proposals from Congress to impose new and stronger sanctions, even though now his administration now takes credit for their success.
When sanctions put Iran on the verge of economic collapse, Mr Obama rushed to offer it a deal. The negotiations to dismantle its nuclear programme began focusing on dismantling the sanctions. The moment the clerics in Tehran began to realise that the military option was not on the table, the US gave up his leverage over them.
The US administration hopes that, on the day after a nuclear deal, the Iranian regime will be different. It definitely will be different: it will be a much more aggressive, confident and powerful government.
To gauge what Iran will look like after a comprehensive deal, simply look at how the temporary nuclear agreement has changed its behaviour. The provisional agreement provided Iran resources to secure its beleaguered ally, Bashar-Al-Assad, in Damascus. The deal gave the Islamic Republic the confidence to mobilise Houthis in Yemen - Saudi Arabia's back yard - to overthrow the Yemeni government and capture the capital.
Iran now controls four Arab capitals: Sana'a, Beirut, Baghdad and Damascus, and is trying to encourage insurgencies in the Shia-populated, oil-rich eastern provinces of Saudi Arabia.
The future looks even worse. The nuclear deal, once complete, will expire after 10 years. Iran will then become a legitimate nuclear state. Iran has been persistently pursuing a nuclear weapon over the past two decades while continuously threatening to destroy other nations. Very obviously, other nations in the region would at least want a similar deal with the US. The age of nuclear proliferation in the Middle East has just begun.
America's failure to intervene in Syria, and its refusal to confront a belligerent Russia, make it difficult to take its promises seriously.
When Sunni states look at the direction of US foreign policy, the fates of Egypt's Hosni Mubarak and the Shah of Iran are now at the forefront of their minds.
The temporary nuclear deal with Iran has already made Middle East a more chaotic place. The comprehensive deal will explode it. A long era of religious wars and nuclear proliferation will be Mr Obama's legacy in the Middle East.
Saeed Ghasseminejad is an Associate Fellow at the Foundation for Defence of Democracies and at its Centre on Sanctions and Illicit Finance