Russian lawmakers late on Tuesday submitted draft legislation that would ban same-sex marriage after voters backed changes to the constitution which define marriage as a union of a man and a woman only. The changes, championed by President Vladimir Putin, were overwhelmingly approved by voters this month in an exercise that opened the door to Putin staying in power until 2036. Critics said the outcome was falsified, something authorities rejected. Putin, who has aligned himself with the Russian Orthodox Church and sought to distance Russia from liberal Western values, has said he will not legalise gay marriage as long as he is in the Kremlin. Enshrining a de facto ban in the constitution means any potential successors would find it hard to legalise same-sex marriage even if they wanted to.