So can promoting equality for gay people be compatible with conservatism?
In discussing this I'm going to take three things as given. And if they're contentious, they shouldn't be.
First, since - on the most conservative estimates - around 5 per cent of the population are attracted to the same sex, there are more than 3 million gay people in the UK and 15 million in the United States.
People often speak of gays as though we are a society apart from the rest, living in our own quarter.
And a few choose to be apart.
But most of us don't.
We live in every city and town.
We are businessmen and women.
We run shops and stack shelves.
We labour on farms and in factories.
We are fire fighters and police officers.
We save lives in hospitals.
We fight for our countries and sometimes we die for our countries.
Some of us are extraordinary, but mostly we are quietly ordinary.
We are not different. And we don't want to be different.
We're not asking for special treatment.
We are United States or British citizens.
Proud of our countries.
Wanting to play our part in society.
And across the world there are millions of us.
Millions of ordinary people.
Millions of voters.
Second, we can't be uninvented. Being gay is not a lifestyle choice. Our sexuality is a fact. It may be repressed, but it cannot be changed.
Doctors don't try to change a person's colour.
And healers or politicians shouldn't try to change anyone's sexuality.
Whether it is given by god, or set by nature, homosexuality isn't nurtured by doting mothers or weak fathers.
It isn't a condition to be cured and it can't be willed away through prayer.
Third, democracies should subscribe to a fundamental principle: that 'all men are created equal'.
Some claim that the promotion of gay equality has no place in conservatism. In fact, many deny that conservatives should be interested in the equality agenda at all.
It is argued that equality is incompatible with liberty ... that if men are free, they are bound to become unequal.
But conservatives who want people to become better through their own efforts can never stand by while others are denied that chance.
Conservatives should always believe that everyone should have an equal chance in life, regardless of any other factors, and that they should not be discriminated against.
As Robert Levy, the Chairman of this Institute, has recently written:
"Thomas Jefferson set the stage in the Declaration of Independence: '[T]o secure these Rights, Governments are instituted among Men.' The primary purpose of government is to safeguard individual rights and prevent some persons from harming others. Heterosexuals should not be treated preferentially when the state carries out that role. And no one is harmed by the union of two consenting gay people."
On the subject of gay marriage, Herbert had this to say:
In his first speech to the Conservative Conference as Leader of the Party - a major event which brings together party activists from across the country - David Cameron said something extraordinary.
Defying the critics who claimed that party leaders could no longer express a moral preference for the institution, he spoke of the importance of commitment and marriage as the bedrock of our society.
But then he added: "and by the way, it means something whether you're a man and a woman, a woman and a woman, or a man and another man."
And when he said these words, the delegates applauded. Not a half-hearted ripple of applause, but a spontaneous burst of approbation.
At that moment, we knew that the Conservative Party and British politics had changed.
David Cameron has put marriage at the centre of our prospectus for the next election, arguing that society is broken, and that we need to recognise the importance of marriage in providing a stable environment in which to raise children.
But in supporting marriage he has not done so in such a way as to denigrate or even exclude gay people.
In fact, the opposite, because we have recognised that commitment and stability are important in all relationships.
I appreciate the view held by some, on a strict reading of their faith, that marriage is a unique arrangement which is only available to a man and a woman.
And we should never dictate to religious organisations who are doing no harm that they should, in their own rites or places of worship, depart from their sincerely-held beliefs.
But in the UK, we created in law a civil union for heterosexual couples, specifically devoid of any religious ceremony and significance for those who do not wish to marry in church.
So what religious grounds could there be for opposing the extension of a secular institution to gay couples through the introduction of civil partnerships in 2005?
And why stand against the extension of a civil institution which demands a public declaration of commitment and stability?
Those who argue against legal recognition for gay partnerships often claim that many gay people have promiscuous lifestyles.
But there are few social incentives of the kind which conservatives should naturally embrace for gay people to embrace commitment.
There's little social support ...
... no institutions to encourage fidelity or monogamy ...
... and precious little religious or moral outreach to guide gay people into what may be seen as more virtuous living.
So it's right to recognise commitment in gay partnerships.
Herbert speaks eloquently about the values that all conservatives should be able to agree on - gay or straight, social conservative or libertarian:
I don't believe that conservatism should be a closed membership club.
We must be open to everyone because we believe that everyone should have a chance.
Conservatism at its most powerful has always been a uniting creed.
We're conservative because we believe in strong defence and the nation state.
We're conservative because we believe in responsibility and justice.
We're conservative because we want to strengthen society and limit government.
We're conservative because we're sceptical about big government and have faith in our institutions and families.
Since Disraeli spoke of 'one nation' we have always understood the importance of maintaining a strong society.
And we have never confused that goal with faith in big government or state action.
The progressive conservatism which David Cameron has espoused is in the true one-nation tradition.
It's about using radical conservative philosophy, politics, and policy to serve truly progressive goals.
It's about fostering local democracy, engagement and accountability by returning power to town halls, neighbourhoods, and individuals.
It's about pursuing a family agenda that lets parents take responsibility for their children's education, allowing them to set up their own schools so that we can give everyone a fair chance in life.
It's about developing bold approaches to tackling poverty and inequality in all its forms, engaging more actively with the voluntary sector and encouraging a revolution in social responsibility.
And it's about recognising that there is such a thing as society, it's just not the same as the state.
If we stand against equality of opportunity, which should be an article of faith for the Right, it becomes the preserve of the Left ...
Warped into an agenda of state interference, targets and central control ...
... when it should be about getting out of people's way and letting them advance.
He has some blunt advice for conservatives who resist supporting gay issues or welcoming gays into the conservative tent:
But I can tell you what happens to a party when it closes the door to sections of our society and is reduced to its core vote. It's no fun being in opposition for thirteen years.
And I can tell you what happens when a Party opens its doors again and broadens its appeal.
A successful political party should be open to all and ought to look something like the country it seeks to govern.