The national unity government made up of the faction of the SLFP loyal to President Maithripala Sirisena and the UNFGG, a coalition headed by Prime Minister Ranil Wickremesinghe’s UNP, is holding together as it nears the two-year mark, despite economic difficulties that forced Sri Lanka to seek an IMF bailout last year, which has committed the administration to implementing unpopular tax measures and structural reforms. Although the economic reform agenda has the potential to strain the relationship between the coalition partners, the inability of Sirisena and Wickremesinghe to reach agreement on proposed changes to Sri Lanka’s constitution probably represents the bigger threat to the survival of the partnership.

The biggest obstacle appears to be Sirisena’s backtracking on a pledge to support the transfer of significant executive power from the president to the prime minister, which was to a large degree the foundation upon which the president and Wickremesinghe built their partnership. The results of a recent poll will do little to help resolve the issue. A survey conducted by the Center for Policy Alternatives earlier this month found that some 60% of respondents preferred to maintain the current system, under which the president instructs the prime minister and members of the Cabinet on day-to-day affairs.

Although the next presidential and parliamentary elections do not fall due until 2021—in January and August, respectively—some observers are concerned that the longer the constitutional process drags on, the greater will be the risk of the entire project being derailed by adverse political developments, such as the collapse of the current coalition or the staging of a snap election that results in the election of a government that does not see constitutional reform as a high priority.

That is not a trivial consideration. The implementation of political reforms designed to promote national unity is among the conditions attached to an agreement with the UN that granted the current government latitude to conduct its own investigation into allegations of war crimes committed in the closing stages of the civil war. If the government fails to deliver, the UN may insist on leading the investigation itself, and Sri Lanka could face sanctions if the government refuses to cooperate.

The government’s efforts to rein in the large budget deficit have focused on increasing the tax take, which is among the lowest in the world. The prospects for near-term progress have dimmed since the Supreme Court ruled that several of the proposed changes to the Inland Revenue Act are unconstitutional, and therefore can only be approved by a majority vote in a national referendum. Given the time required to organize a referendum, and the distinct possibility that voters would reject the reforms, officials will be tempted to pursue the path of least resistance by striking the problem clauses from the text and pushing the legislation through to passage, an expedient that is unlikely to be judged acceptable by the IMF.