President Donald Trump announced on May 8, 2018 that he was pulling the United States out of the 2015 Iran nuclear deal, arguing that the international accord was not in America's "national interest." The decision threw a cloud of uncertainty over the future of the nuclear accord and raised tensions with US allies in Europe.

Britain, France and Germany lobbied the Trump administration and Congress to remain in the nuclear accord, arguing that the deal was working and a US violation without a follow up plan would be destabilizing. In European capitals, the Trump administration's withdrawal was viewed as a slap in the face of allies.

A year to the day after Trump's announcement, Iran informed the other signatories of the accord that they would no longer adhere to certain "voluntary commitments." Iranian President Hassan Rouhani said the signatory nations had 60 days to implement promises to protect Iran's oil and banking sectors or Iran would resume the enrichment of uranium.

The decision came after the United States deployed an aircraft, the USS Lincoln, along with a bomber task force to the Middle East. Washington said the deployment was intended as a "clear unmistakable message." Iran said it took action because the European Union and others "did not have the power to resist US pressure."

The Joint Comprehensive Plan of Action (JCPOA), better known as the Iran nuclear deal, was signed in 2015 by United States, China, Russia, France, Germany and Britain (P5+1) and Iran following years of negotiations. Under the international agreement, Iran agreed to dismantle its nuclear program and be subject to monitoring in exchange for the lifting of international nuclear related sanctions.

The JCPOA includes a robust monitoring, verification and inspection regime carried out by International Atomic Energy Agency (IAEA). The UN watch dog has verified Iran's compliance with the deal in 12 quarterly reports. The JCPOA allows Iran to pursue a peaceful nuclear program for commercial, medical and industrial purposes in line with international non-proliferation standards.

The Iran nuclear deal was President Barack Obama's signature foreign policy achievement. Seeking to undo nearly every Obama administration legacy, Trump came into office calling it the "worst deal ever." The Trump administration argues the nuclear deal doesn't address other unrelated issues such as Iran's ballistic missiles, regional influence, support for "terrorist" groups and human rights.

The nuclear deal and lifting of punishing nuclear related international sanctions created optimism in Iran after years of economic isolation. However, even before Trump pulled the US out of the deal, Tehran blamed the US for holding back international investment and not fulfilling its end of the bargain due to the uncertainty created by Trump's threats.

After eight years with Barack Obama, Israeli Prime Minister Benjamin Netanyahu found the US president he wanted in Donald Trump. The Israeli leader repeatedly slammed the deal despite his own military and intelligence chiefs' assessment the that JCPOA, while not perfect, was working and should be maintained. Saudi Arabia and the UAE are the other main opponents of the nuclear deal.

The EU-3 (Britain, France, Germany) have scrambled to ensure that Iran receives the economic benefits it was promised in order to avoid Tehran pulling out of the deal. As EU businesses face retaliation from the US for doing business with Iran, many are opting to avoid Iran. This would likely be a present to Chinese and Russian businesses.

US sanctions on Iran target Tehran's trade in gold and precious metals, block the sales of passenger jets and restrict Iran's purchase of US dollars, among other punitive measures. The US has also blocked Iran's key oil sales in a further tranche of sanctions, which came into force in November 2018.

Impoverished North Korea is under a UN-backed embargo, but Washington also maintains an extensive regime of sanctions of its own. For example, the US strictly bans exporting weapons to the pariah state. Washington also uses its global clout to penalize non-US banks and companies that do business with Pyongyang.

Washington trade restrictions prevent the regime of President Bashar Assad from exporting Syrian oil to the US. All property and assets of the Syrian government in the US have been frozen. Americans, wherever in the world they might be, are banned from "new investment" in the war-torn country, according to the US Treasury.

The US blacklisted scores of high-ranking Russian officials and businessmen after the 2014 Crimea crisis, stopping them from traveling to the US and freezing their assets. The comprehensive sanctions list includes goods from the Russian-annexed region, such as wine. New sanctions imposed in the aftermath of the Skripal poisoning in March 2018 target sensitive national security and defense goods.

American tourists began flocking to Cuba immediately after the Obama administration initiated a thaw in relations in 2016. Under Donald Trump, however, the White House reimposed travel restrictions for US citizens, making it much harder for Americans to travel to the island. At least one Obama-era concession is still in place, however: it is still legal to bring Cuban cigars and rum to the US.