With the Marriage (Same-Sex Couples) Bill still making its way through the House of Lords, it's probably too early to say what the longer-term impact of the debate will be on domestic politics generally, or indeed on the Conservative Party in particular.
It would be wrong, however, to see this as a purely "British" or "domestic" discussion. The end of May saw the first gay marriage in France, which witnessed arguably an even more intense debate than seen here in Britain. Across the pond, we await a judgement from the US Supreme Court due later this week.
Where is public opinion in all this? A new Ipsos study provides some timely evidence. It suggests that, in making legal changes to the rights of same-sex couples, politicians and legislators are broadly in line with public opinion.
The poll, conducted in 16 developed markets around the world finds 73% in favour of some form of legal recognition of same-sex marriage, including 52% who support full marriage equality.
David Cameron will note that Britain is one of the countries most in favour of gay marriage, with 66% in support. It's worth noting that most people in this country (58%) now have a work colleague, friend or relation who is lesbian, gay, bisexual or transgender (LGBT), a pattern which is by no means the case in all countries covered in the survey. In Japan, 5% say they know a work colleague, close friend or relative who is LGBT and 3% of South Koreans say this.
British people are also more likely to be supportive of same-sex couples bringing up children. Internationally, most people (59%) agree that they should have the same rights to adopt children as heterosexual couples. In Britain, it's 65%. Similarly, 64% of respondents say that same-sex couples are just as likely to do a good job at raising children (72% in Britain).
Japan, Poland, South Korea and Hungary are the countries least in favour of legal recognition of same-sex relationships. People in these countries do however recognise that same-sex couples should be able to have their marriage recognised in their country if they have been married in another country.
This is an issue where public opinion may have been fluid - one in three say they have changed their views on the matter over the last five years. We don't know exactly how or in which direction their attitudes may have changed, but it does seem likely to have been flowing towards what we see today: one of broad support for legal recognition of same-sex couples, albeit support which falls some way short of being a consensus.