The Sri Lankan government is poised to crush the Tamil Tiger rebels and end a quarter-century civil war that has killed tens of thousands. But it still faces a major challenge beyond the battlefield: resolving the ethnic conflict that fueled the uprising. President Mahinda Rajapaksa has consistently expressed support for a deal to give the ethnic Tamil minority on this South Asian island nation more say in a government long dominated by the Sinhalese majority. “The sowing of discord belongs to the past. The future belongs to those who sow the seeds of unity,” he said in a speech Wednesday marking Independence Day.