US President Barack Obama says he cannot imagine a state’s same-sex marriage ban being constitutional.

Up until now, President Obama has expressed personal support for equal marriage, but said the issue should be decided on a state-by-state basis.

However, in an interview released on Wednesday, President Obama signalled a new position.

ABC News’ George Stephanopoulos asked President Obama whether same-sex marriage was a right under the US Constitution.

He replied: “Well, I’ve gotta tell you that, in terms of practical politics, what I’ve seen is a healthy debate taking place state by state, and not every state has the exact same attitudes and cultural mores. And I… you know, my thinking was that this is traditionally a state issue and that it will work itself out.”

But President Obama then suggested that the spirit of the US Constitution should take precedent in the equal marriage debate.

He said: “On the other hand – what I also believe is that the core principle that people don’t get discriminated against – that’s one of our core values. And it’s in our constitution.”

George Stephanopoulos then asked whether President Obama could imagine a circumstance where a state’s equal marriage ban could pass constitutional muster.

“Well, I can’t, personally. I cannot,” the president replied.

“That’s part of the reason I said, ultimately, I think that, same-sex couples should be able to marry.

“That’s my personal position. And, frankly, that’s the position that’s reflected – in the briefs that we filed – in the Supreme Court.”

Last month, the US Justice Department filed a brief with the US Supreme Court urging the nine justices to overturn Proposition 8, California’s voter-approved ban on equal marriage.

Shortly afterwards President Obama said that if he sat on the US Supreme Court, he would most likely rule that same-sex marriage bans were unconstitutional.

The Supreme Court is due on 26 March to take up the case of whether to overturn the 2008 law.