US President Donald Trump pulled the United States out of the Iran nuclear deal and reimposed sanctions on the Middle East country on Tuesday. The deal, formally known as the Joint Comprehensive Plan of Action, was signed by the five permanent members of the UN Security Council (the US, Russia, China, Britain and France), Germany and Iran in Vienna on July 14, 2015, after 18 months of negotiations, and immediately approved by the Security Council.

Iran suspended its nuclear weapons program in exchange for the international community withdrawing some of its sanctions against the country. Although the deal allows Iran to retain its nuclear potential and is thus not restrictive enough, it prevents Teheran from crossing the nuclear threshold to develop nuclear weapons. In a way, the deal preempts another war and sets an example for future nuclear nonproliferation negotiation.

Among the six world powers that signed the deal, the US was the only one hostile toward Iran. So its consent was critical. Former US president Barack Obama, determined to leave behind a diplomatic legacy of peace, changed his stance on the Iranian nuclear issue and agreed to the deal. In the process, he even offended his allies, Israel and Saudi Arabia.

The year 2016, however, was a political turning point for the US. Traditional political elites were sidelined as Trump won the presidential election by embracing populism. Trump has overturned very much everything his predecessor did, so his withdrawal from the Iran nuclear deal should not have come as a surprise to many.

Since Iran has been demonized in the US since the overthrow of Mohammad Reza Pahlavi in 1979, Obama's signing of the nuclear deal with Iran enjoyed weak public support in the US. As a result, Trump didn't encounter much domestic opposition when he called the Iran deal "the worst deal ever", or when he withdrew the US from it.

At a time when the Democrats and the media have been highlighting Russia's alleged involvement in the 2016 presidential election, and the Republican Party is losing seats in the Congress, Trump pulled out of the Iran nuclear deal in a bid to win more domestic support and ensure the Republicans do not lose in the US midterm election.

Iran's nuclear program threatened to break Israel's nuclear monopoly in the Middle East. To prevent Iran from actually developing a nuclear weapon, Israel sought further US support. But the signing of the nuclear deal by Obama dealt a serous blow to US-Israeli relations. Trump had opposed the deal right from the days of his presidential campaign, and within 100 days of being sworn in as US president, he visited Israel. And soon, he announced that the US would shift its embassy from Tel Aviv to Jerusalem, despite Israel and Palestine both claiming it to be their capital.

A week before Trump announced the US' withdrawal from the Iran nuclear deal, Israeli Prime Minister Benjamin Netanyahu claimed that "evidence" of Iran developing nuclear weapons had been found. This, many believe, could have influenced Trump's decision.

The Israel lobby, which is a decisive force in US politics, will definitely make full use of its financial power and social influence to tilt public support in favor of Trump. No wonder many believe Trump has killed two birds with one stone.

The consequences of the US abandoning the Iran nuclear deal are obvious. To begin with, it will increase the risk of war in the Middle East. Although Iran has said it will remain in the nuclear deal, it might restart its nuclear program if the US imposes more sanctions on it and pressures other countries to follow suit, which could deal Iran's oil exports another big blow. Iran could restart the 10,000 sets of centrifuges that have been turned off, and resume uranium enrichment to the 20 percent level.

In fact, Iran could cross the threshold to develop nuclear weapons soon. Once that happens, Israel may not hesitate before launching a military strike on Iran's nuclear facilities. The US could then be dragged into the quagmire, leading to a catastrophic war, which in turn could plunge the global economy into utter chaos, leaving the world to pay for Trump's mistakes.

Trump's decision on the Iran deal has also damaged the US global image. Besides, his inconsistent actions will turn into ashes the efforts of the international community (and the United Nations) to resolve the nuclear proliferation issue through negotiations. Trump's reckless actions have subverted the traditional diplomacy of the US and raised the international community's concerns over future world security.

However, the world is fast changing and the days when the US exercised hegemony over other countries are past. For more than a year, Trump's diplomacy, from the North American Free Trade Agreement, the Trans-Pacific Partnership trade pact and the Paris climate deal to the Korean Peninsula nuclear issue and the Syrian civil war, can be described as loud thunder but little rain. This time, while withdrawing from the Iran nuclear deal, Trump kept the promise he had made to his voters but did not force the US allies, or China and Russia to follow in the US' footsteps. This shows he is trying to avoid risks by hiding behind his shield of strong words.

The Iran nuclear deal is a product of compromise. That the US has been criticized by even some of its European allies for abandoning the deal shows it is really lonely in the world.

The author is a former Chinese ambassador to Iran.