In today’s Supreme Court hearing around Proposition 8, the state of California’s ban on equal marriage, the justices questioned the meaning of marriage, and challenged arguments for the ban.

After Tuesday’s oral arguments, the court could uphold the 2008 state ban, overturn it just in California, or invalidate all state same-sex marriage bans in the US.

Defenders of the state-wide ban argued that each individual US state should be able to decide on the issue.

Some argued that the court was backing away from making a groundbreaking decision on equal marriage. One possibility is that the court will decide to not rule on the case, leaving Proposition 8 in place.

Justice Anthony Kennedy, widely regarded as the swing vote between justices on the liberal and more conservative side of the court, described today’s case as “uncharted waters”.

He continued: “We have five years of information to pose against 2,000 years of history or more,” he said, but went on to suggest that children of same-sex couples could face an “immediate legal injury”, if Prop 8 were to stand.

He questioned whether the case should even have gone to the Supreme Court.

The justices went on to discuss whether the argument of procreation could be linked to the legal definition of marriage.

Responding to Charles Cooper, a lawyer arguing that procreation was fundamental to marriage, Justice Stephen Breyer said: “There are lots of people who get married who can’t have children.”

Justice Sonia Sotomayor asked Cooper to identify injuries caused to proponents of the ban, to which he responded: “I cannot.”

Justice Ruth Bader Ginsburg also raised a previous Supreme Court ruling which allowed prison inmates the right to marry, despite being prevented from procreation.

The Supreme Court will also on Wednesday begin to consider an appeal against The Defense of Marriage Act, urged on by President Obama and even Bill Clinton, the former President who signed DOMA into US law.

A decision by the Supreme Court in both cases is expected by the end of June.

Several polls released recently have found that support for equal marriage in the US has shifted greatly, and is an at all time high. 

Two Democratic Senators came out in support of same-sex marriage ahead of the Supreme Court’s hearings on the subject.

Missouri Democratic Senator Claire McCaskill already came out in support for marriage equality earlier on Monday, via a Tumblr post.

Aside from the Democrats to have come out as pro-equality, Republican Senator Rob Portman announced that he  endorsed same-sex marriage on 15 March.

The former US Secretary of State Hillary Clinton, officially announced her support for equal marriage in a moving speech last week in which she called moves towards equality “breathtaking and inspiring”.