BRUSSELS – Three years ago, Sri Lanka elected Mahinda Rajapaksa as president because he pledged to take the offensive against the Liberation Tigers of Tamil Eelam, the guerillas who have been fighting for 25 years to carve out an independent homeland for the country’s Tamil minority. Many well-meaning people saw Rajapaksa’s promise as warmongering, and, even as Sri Lanka’s army has been pressing toward victory, urged him to negotiate with perhaps the world’s most fanatical terror organization (the Tamil Tigers, it should be recalled, virtually invented the cult of the modern suicide bomber.)