Celebrities like to support causes, but there’s a general sense that while they some give money, turn up and have their picture taken and say nice things on Twitter, the people of Hollywood don’t really make much difference when it comes to social issues. However that may not have been true with yesterday’s US Supreme Court decisions on DOMA and Prop. 8, where various Hollywood figures were central to the fight.

Back in 2008 a court decision that not allowing gay people to marry was unconstitutional suddenly made same sex marriage legal in California. However a ballot measure in the November elections – Proposition 8 – sought to end that by adding an amendment to the State Constitution saying ‘only marriage between a man and a woman is valid or recognized in California’. It passed with 52.24% of the vote, ending same sex marriage and leaving the thousands who’d already married in a legal limbo.

However campaigners weren’t going to take this lying down. After the measure passed, various campaigners, including director Rob Reiner (This Is Spinal Tap, When Harry Met Sally), met at the Hollywood setting of the Polo Lounge to discuss mounting a legal challenge to Prop 8, arguing that irrespective of an individual state’s constitution, the overall US Constitution guarantees equal protection under the law.

To do that they needed money, and a large part of the seed cash for the legal battle came from David Geffen (the ‘G’ of Dreamworks SKG) and JJ Abrams (Star Trek Into Darkness). Reiner and political strategist Chad Griffin then founded American Foundation for Equal Rights (AFER) to fight the battle.

AFER has since attracted other Hollywood names, such as Milk screenwriter Dustin Lance Black, who joined its board. He also wrote the play ‘8’, about the trial to overturn Prop 8, which saw the likes of Brad Pitt, George Clooney, Martin Sheen, and Kevin Bacon appearing in a staged reading last year, in order to raise money for the fight.

There was another Hollywood figure who was perhaps even more key to the Supreme Court’s decision not to hear the Prop 8 case and that’s Arnold Schwarzenegger. As Governor Of California – and a Republican Governor at that – he took the decision that his administration would not defend the Proposition in court (it would normally be the Attorney General or the Governor who’d be expected to officially defend it). In fact the case that ended up at the Supreme Court was officially known as Perry Vs. Schwarzenegger when it was first filed, but Arnie conceded that Prop. 8 was not constitutional and so refused to fight for it in court.

As a result of Schwarzenegger and his successor Jerry Brown’s decision not to defend the case, the coalition of anti-gay marriage groups behind the original attempts to get Prop. 8 on the ballot got together to defend it. After a huge amount of legal manoeuvring, most of which the Prop 8. proponents lost, the case ended up at the highest court in the US.

The Supreme Court then decided they could not look at the case because those anti-gay marriage groups did not have legal standing to mount the case (as they could not prove they’d been harmed), which essentially meant that the original District Court ruling that Prop 8 is unconstitutional now stands. As a result, same sex marriages should now resume in California soon.

The fact is, if Arnold Schwarzenegger and Jerry Brown had decided to defend the measure in the first place, this question of who had the right to defend Prop. 8 would have never come up. It would also have meant the arguments for the Proposition would have been a lot stronger (many have criticised the anti-gay marriage side’s shoddy lawyering) and the outcome could well have been different.

Many other celebs did their bit too, such as Ellen Degeneres submitting a friend of the court brief to the Supreme Court and Clint Eastwood signing his name to a list of prominent Republicans who support gay marriage.

Of course many, many other people were involved in the fight too, but this really is a case where the people of Hollywood made a difference and that without the likes of Rob Reiner and Arnold Schwarzenegger, there might have been a different outcome yesterday. Tinsel Town certainly didn’t win single-handedly, but it definitely helped.

Rob Reiner also said a few months ago that he’s hoping to direct a film version of 8, which he hopes will help with the equal marriage fight in the rest of the US – so perhaps Hollywood influence in this battle isn’t over yet.