After Denis Sassou Nguesso returned to power in the 1997 civil war, a new constitution was approved in the January 2002 constitutional referendum. The 2002 constitution provided for a strong executive presidency, without a prime minister, and weakened the legislature; the length of presidential terms was increased to seven years (with a limit of two terms), and an age limit of 70 years for presidential candidates was established, apparently to exclude Sassou Nguesso's most important political opponents, who had either reached that age or were nearing it. Parties opposed to Sassou Nguesso criticized the new constitution and called for the people to boycott the 2002 referendum.