Sri Lanka's raucous political scene is poised to become even more tumultuous in the coming year. Once notorious as the home of the Liberation Tigers of Tamil Eelam, a militant group better known as the Tamil Tigers, Sri Lanka resolved its decadeslong civil war in 2009. But in the years since the government's victory over the Tamil Tigers, the underlying tension between Sri Lanka's Buddhist ethnic Sinhalese majority, 75 percent of the country's population, and the Hindu ethnic Tamil minority has persisted. Now, Tamil and Sinhalese leaders in Sri Lanka are at odds over the country's political future, complicating President Maithripala Sirisena's plans to enact constitutional reforms. To make matters more difficult for the current administration, former President Mahinda Rajapaksa -- who lost power in a 2015 electoral upset -- promised in late December to "topple" Sirisena's government this year. Already, Rajapaksa has proved a formidable political foe as the...