Original sentence: The new Constitution, approved by referendum in June 1992, enabled the election of a new parliament in September 1992, based on restrictive citizenship laws that disenfranchised a third of Estonian population
Edited sentence: The new Constitution, approved by referendum in June 1992, enabled the election of a new parliament in September 1992, based on the pre-1940 citizenship law that did not provide automatic citizenship to post-1940 immigrants and their descendants (at the time  nearly 30% of the population of Estonia)