Far from benefitting the U.S., Trump’s North Korea strategy advantaged Pyongyang and Beijing. Trump indulged Kim in Singapore, promised to cancel military exercises with South Korea and relaxed pressure on North Korea. So why is North Korea backtracking, and why would Tehran not see benefit in replicating the Singapore Summit?

Reality check: While engaging Trump could be an opportunity for Pyongyang and Tehran to secure results unfathomable under any other U.S. president, it's also unclear whether Trump would be able to deliver on them, and whether agreements made now would hold after he leaves office.

In Kim's and Rouhani's eyes, the Woodward book and the anonymous op-ed have likely heightened the expectation that the Mueller investigation and possible party setbacks in the midterms could weaken Trump and mire his administration in taxing wars of attrition with Congress. Better not to get into deal-making with a president whose fortunes are uncertain, and whose unorthodox initiatives are bound to be discarded quickly by his successor.

The bottom line: North Korea's and Iran’s postures are not unique. Friends and foes across the world have adopted a wait-and-see approach. Trump’s troubles at home have weakened his hand abroad, and that trend will only intensify if the Democrats take the House in November or the Mueller investigation gets closer to the president.

Vali Nasr is dean of the Johns Hopkins School of Advanced International Studies.

Ironically, given how Trump has handled the two cases, the sympathy of our allies and the broader international community lies with Iran and North Korea. He has alienated U.S. allies just when he needs them most, to the benefit of geopolitical rivals: Much to Russia's delight, the demise of the Iran deal has created a rift between the U.S. and its European allies, while the collapse of the Trump–Kim summit has put the U.S. at odds with South Korea, which suits China.

The administration’s strategy can be boiled down to the hope that “maximum pressure” will compel Iran and North Korea to accept new deals. But why would they? The threat of maximum pressure rings hollow when there is scant support for it among U.S. allies. Nor is it convincing that the U.S. would be able to effectively apply maximum pressure on both Iran and North Korea at the same time.

The bottom line: The global expectation now is that Washington will fail. That does not bode well for U.S. foreign policy.

Vali Nasr is dean of the Johns Hopkins School of Advanced International Studies.

First, North Korea already has nuclear weapons, which Kim Jong-un considers sufficient leverage to negotiate effectively with U.S. By killing the Iran deal, Trump will only convince Tehran that it should secure similar leverage — a bigger nuclear program, perhaps even nuclear weapons — before resuming talks. Trump may also find it difficult to squeeze Iran while continuing to squeeze North Korea, potentially giving Iran even more time to work with. After all, to keep North Korea talking and ultimately making concessions will require concerted and ongoing U.S. pressure.

Second, Iran has a true domestic politics with many competing factions, despite its authoritarian edifice. Although an absolute dictator may be swayed, Iran’s leaders, jostling for power and position, won’t bow to brazen intimidation any more than American politicians would. In fact, Trump’s tactics will likely embolden hardliners in Tehran, who will see an opportunity to sideline rivals tainted by an association with the U.S. — in which case everything that worries the U.S. about Iran will only get worse.

Why it matters: It’s a mistake for Trump to follow his North Korea model — which is still being tested — in deciding the fate of the Iran nuclear deal. A victory for hardliners in Iran will only put the U.S. in a more difficult negotiating position down the line, with much higher stakes.

Vali Nasr is dean of the Johns Hopkins School of Advanced International Studies.