The US Supreme Court yesterday declined to decide once and for all whether states can ban gay marriage, a surprise move that will allow gay men and women to marry in five states where same-sex weddings were previously forbidden. By rejecting appeals in cases involving Virginia, Oklahoma, Utah, Wisconsin and Indiana, the court left intact lower-court rulings that had struck down the bans in those states. But the high court's action means there will be no national ruling yet on the issue, with litigation in states where gay marriage is still banned likely to continue. "Any time same-sex couples are extended marriage equality is something to celebrate, and today is a joyous day for thousands of couples across America," Chad Griffin, president of the gay rights group Human Rights Campaign, said. Other states under the jurisdiction of appeals courts that have struck down the bans will also be affected by the Supreme Court's decision, meaning the number of states with gay marriage is likely to jump quickly from 19 to 30. The other states would be North Carolina, West Virginia, South Carolina, Wyoming, Kansas and Colorado. The court's move yesterday could send a strong signal to lower court judges that rulings striking down marriage bans are consistent with the US Constitution. Gay couples in the affected states may seek to get married immediately, because the high court's action means that the appeals court's rulings are no longer on hold. The high court's decision not to hear the cases was unexpected. Most legal experts believed it would want to weigh in on a question of national importance that focuses on whether the US Constitution's guarantee of equal treatment under law means gay marriage bans were unlawful. The message sent by the court in declining to hear the matter will be a boost to gay marriage advocates involved in similar litigation in states that still have bans on the books. In June last year, the justices ruled 5-4 to strike down a key part of a federal law that had restricted the definition of marriage to heterosexual couples for the purpose of government benefits. That decision led to a series of court rulings favouring gay marriage in numerous states. In a separate same-day case, the justices sidestepped the broader question of whether state bans violated the Constitution but allowed gay marriage to move forward in California.