Welcome to The Adversarial. Every other week, we’ll provide you with expert analysis on America’s greatest challengers: China, Russia, Iran, North Korea, and jihadists. Read more below.***IranThree weeks after it was signed, the memorandum of understanding between the United States and Iran seems to be quickly unravelling. The two sides skirmished after an April ceasefire and continued to do so after the memorandum of understanding was reached, but had managed to keep those tit-for-tat exchanges from escalating into a full-on return to hostilities. Their agreement nonetheless faced death by a thousand cuts over mutual claims of violations and bad faith.A string of attacks on tankers traveling in and around the Strait of Hormuz, Iran’s latest effort to flex its control over the contested chokepoint, led the Trump administration to withdraw one of the deal’s key financial incentives. On July 7, the Department of the Treasury revoked the sweeping 60-day general license that had allowed for the sale of Iranian oil and petrochemical products. The United States followed this economic measure with strikes against naval and defensive assets. Iran retaliated with drone and missile attacks in Qatar, Kuwait, and Bahrain.If, as Trump hinted on Wednesday, the United States resumes its naval blockade of Iran or expands strikes, fitful negotiations could be quickly outpaced by military escalation.A lineup of various Iranian military vehicles. Image: Hadi Hirbodvash via Wikimedia CommonsRussia Russia and Ukraine have both accelerated missile and drone attacks over the last two weeks. The deadliest attack, which struck Kyiv on July 2, killed at least 22 people and injured dozens. Russia’s Ministry of Defense framed the attack as retaliation for Ukrainian strikes on civilian infrastructure in Russia. The ministry also said it hit military and energy facilities around Kyiv and military airports in several regions. Ukraine has become increasingly vulnerable to such strikes