Sri Lanka's bitter power struggle
(CNN) -- The political crisis that has shaken Sri Lanka stems from a long-running rivalry between the country's prime minister and president.
In the one corner stands President Chandrika Kumaratunga, the latest in a line of political heavyweights -- both her parents were prime ministers. Her mother was the world's first woman prime minister.
But the Kumaratunga dynasty was thrown out of power two years ago by her political nemesis, Ranil Wickremesinghe.
Prime Minister Wickremesinghe's United National Front swept aside Kumaratunga's Sri Lanka Freedom Party in parliamentary elections held in December 2001.
At the center of their dispute -- how to bring an end to two decades of civil war against rebels demanding a separate homeland for the country's minority Tamil community.
The war has claimed the lives of more than 65,000 people and cost the island's economy hundreds of millions of dollars.
Both the president and prime minister believe that a lasting peace is the only way for Sri Lanka, one of Asia's poorest countries, to develop.
Beyond that, they agree on little else.
Since the 2001 vote, the two rivals have been locked in an uncomfortable constitutional cohabitation -- in effect a thinly-disguised power struggle.
Under Sri Lanka's constitution Kumaratrunga's presidency has wide-ranging executive powers with ultimate responsibility for law, order and security and command of the country's armed forces.
Constitutionally the president, who is elected separately, also has the power to sack the government and dismiss ministers -- but until Tuesday no president had ever exercised that power.
Shadow over peace process
Where under the constitution the prime minister stands in all of this is not clear, casting a shadow over the future of the peace process.
Kumaratunga herself claims credit for kick-starting negotiations with the Tamil Tigers, inviting Norway to help broker peace talks with the rebels after she narrowly avoided death in a 1999 assassination attempt.
That initial effort ground to a halt amid an upsurge in fighting, but was given new life when Wickremesinghe's government took power promising to bring an end to the war once and for all and allow the island nation to reap the economic benefits of peace.
Since then Kumaratunga has been an ardent critic of the government's handling of negotiations, although not directly a critic of the peace process itself.
Too many concessions have been too easily given away, she says.
According to Kumaratunga the government has compromised issues of sovereignty in its negotiations with the Tamil rebels, ultimately threatening the security of the Sri Lankan state.
What exactly was the final straw is unclear but on Tuesday, with the prime minister out of the country on a visit to the U.S., it seems Sri Lanka's president had decided the time had come to exercise her wide-ranging powers.