By Leonid Bershidsky\u00a0 As important as it is, the great nuclear power quarrel over the Intermediate-Range Nuclear Forces Treaty of 1987 is about more than any particular agreement. The dispute raises the question of whether treaties remain relevant when some leaders are unwilling to be held to any obligations and others are too weak to challenge them. On Tuesday, US\u2019s secretary of state Mike Pompeo demanded that Russia comply with the INF treaty within two months or face a US withdrawal from the treaty. Specifically, the US and its North Atlantic Treaty Organization allies want Russia to scrap a missile known as the SSC-8 or 9M729, which, they claim, has a longer range than is allowed under the treaty. Russia says the missile has a shorter range and complies with the agreement. In addition, Moscow accused the US of violating the treaty. According to the Russian foreign ministry, the Aegis Ashore weapons systems, elements of both the US anti-missile defence and its drone program don\u2019t comply with the INF\u2019s letter, spirit or both. Moscow isn\u2019t about to make concessions and seems to believe the treaty is already dead. On Wednesday, Valery Gerasimov, Russia\u2019s chief of general staff, told foreign military attaches in Moscow that if the US abandons the treaty, Russia will target any countries where US intermediate-range nuclear missiles are deployed. That threat could lead to a standoff much like the 1980s confrontation between the Soviet Union and European NATO members that agreed to house US Pershing II missiles. But these tensions obscure a more troubling general picture. Both the ultimatum and the tough response are about optics: The US wants to be able to say it gave the Russians fair warning, and Russia, in turn, is trying to persuade the world that the US has long since made up its mind to tear up a treaty that constrained it too much. Substantively, however, the dispute is about both sides\u2019 willingness to comply with any mutual constraints at all. Russia\u2019s president, Vladimir Putin, has shown time and time again that expediency is more important to him than any pre-existing agreements. The land grabs in Ukraine and the obstacles Russia puts up for ships headed to Ukrainian ports on the Sea of Azov are, in Putin\u2019s mind, justified by geopolitical or security considerations. These justifications take priority over pieces of paper signed by his predecessors. Whether Putin will stick to a deal depends on whether he can get away with not complying. That makes it difficult to negotiate anything with him: The Russian leader has argued repeatedly that enforcement mechanisms such as economic sanctions cannot make Russia change its behaviour. US president Donald Trump, for his part, has shown a similar unwillingness to be constrained by bilateral or multilateral agreements. This reticence applies to even \u201cshallow\u201d deals such as the Paris climate pact of 2015, from which Trump exited, or the new United Nations migration pact, which his administration refused to sign. In the case of deeper and more specific agreements, Trump only feels constrained when he deems the US has enough to gain. This logic motivated the renegotiation of NAFTA and the repudiation of the 2015 Iran nuclear deal. Trump approaches negotiating partners from a zero-sum position of strength\u2014a more muscular version of the traditional US hegemonic position above any kind of international law. Any deal between the US and Russia has always been personal, an agreement between two specific leaders that reflects the chemistry of their relationship. The INF treaty was a deal between president Ronald Reagan and the Soviet leader, Mikhail Gorbachev. For all their differences, and regardless of Gorbachev\u2019s growing economic desperation, they shared an agenda of establishing lasting peace. The arms-control treaties they signed, sometimes surprising each other with how much they dared to give up, reflected their intentions; even without strong enforcement mechanisms, they could trust each other because they shared a goal. There was similar chemistry between Russian president Boris Yeltsin and his US counterparts, George HW Bush and Bill Clinton. The connection ensured that old deals worked and new ones were signed. One could argue Russia\u2019s weakness was a more important factor, but Russia is still considerably weaker than the US\u2014and that no longer helps keep deals together. Personal deals between US and Russian leaders haven\u2019t been possible for years for a variety of reasons, not least a disunity of goals. There is, however, an argument to be made that deals in general don\u2019t work as well as they usually have in recent decades. In October, a group of intellectuals from the Valdai Club, the international relations think tank and discussion club close to the Kremlin, published a report entitled \u201cLife in a Crumbling World\u201d. \u201cOn the whole, international relations are shifting toward less and less binding interactions\u201d, Fyodor Lukyanov and collaborators wrote. \u201cEveryone proceeds from the belief that peace is reliably guaranteed even under the conditions of a political conflict between countries\u201d. That\u2019s a convenient justification for Putin\u2019s treatment of agreements as, alternately, fig leaves or wasted paper. But there is also truth in the idea that, in the absence of threats as overwhelming as that of a big war, no deal is enforceable. This isn\u2019t only true of agreements between the US and Russia. European powers, normally sticklers for international rules, haven\u2019t done much to keep the Iran nuclear deal alive in the face of US sanctions. The weak response to Trump\u2019s pressure must be deliberate as Europe has the international weight and wealth to try much harder. Even within the European Union, compliance with agreements concerning the rule of law or solid economic management is slipping. Country after country is testing the limits of the possible. And while the UK and the EU have been trying hard to reach a divorce deal, compliance with any agreement doesn\u2019t feel preordained. Former Bank of England governor Mervyn King suggested recently that if the current version of the deal stands, the UK is likely to abrogate it unilaterally. In their report, Lukyanov and collaborators wrote that countries are increasingly selfish in their interactions. That rings true. The question is what kind of threat could bring the leaders of this fractured world to start making binding deals again. A military incident reviving the threat of a global conflagration? The possibility of another all-encompassing economic crisis? Until that question is answered, it is safe to assume no deal, bilateral or multilateral, can withstand pressure. The INF treaty, which in better times would have been discussed constructively and amended by leaders who believed in win-win solutions, is just one case in point. This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.