While campaigning for her husband in New York City, First Lady Michelle Obama twice reminded people that it is the president who makes appointments to the US Supreme Court and that those appointments could impact gay marriage.

At an event hosted by actor Robert De Niro on Monday (19 March), the First Lady said: 'Let us not forget what [the Supreme Court's] decisions - the impact those decisions will have on our lives for decades to come - on our privacy and security, on whether we can speak freely, worship openly, and, yes, love whomever we choose.'

Mrs. Obama said virtually the same thing earlier in the day at an event in Chelsea.

White House press secretary Jay Carney was later asked about the First Lady's comments by MetroWeekly and he said: 'The president and first lady firmly believe that gay and lesbian Americans and their families deserve legal protections and the ability to thrive just like any family does. The first lady has said she is proud of his accomplishments, including the repeal of 'Don't Ask, Don't Tell,' ensuring hospital visitation rights and calling for the repeal of DOMA and obviously our actions on [the Defense of Marriage Act]. And our decision not to defend DOMA is well known.'

President Barack Obama has famously remained neutral on the gay marriage issue throughout his first term. He officially is opposed to it and in favor of civil unions but has said he is 'evolving' on the issue.

Who is sitting on the Supreme Court may have a historic impact on gay marriage in the US if the court ends up ruling on the federal lawsuit that overturned California's Proposition 8 last month.

That ruling is being appealed by Prop. 8 proponents and a likely scenario is that the Supreme Court will be asked to get involved. It can either decide not to hear the case and allow the ruling to stand, or set the stage for the ultimate legal battle over same-sex marriage.

Since taking office in 2009, Obama has nominated two women to the nine-member Supreme Court: Elena Kagan and Sonia Sotomayor.