Steve Baker is co-Chairman of Conservatives for Britain and is MP for Wycombe.

We live in an amazing moment for the Conservative Party. After a difficult Parliament, the electorate has given us a clear if slim mandate. It is a time of opportunity which we must not squander, whatever challenges we face.

In roughly over 1760 days, polls will close for the General Election of 2020. Meanwhile, the referendum on our membership of the European Union will shape the future of our country and our party as it tests our capacity for unity.

In politics, unity is powerful but difficult. Effort is required to remain together despite our differences, and differences there most certainly will be on this question. How we handle those disagreements now and in future will define the resilience of our relationships and our chances of avoiding breakdown.

Handling foreseeable differences of opinion may require attitudes which are at odds with our usual battles. As we wrestle in public with our opponents for power, pride is more likely than humility, yet it is humility which enables us to hear the convictions of those fighting beside us. In a struggle, it is easy to be brutal, yet gentleness avoids many lasting injuries. When there is a demand for quick results, patience is in short supply, yet it is patience which enables us to bear with one another in a spirit of friendship.

Why should we bother to make this effort?

We live in a time of extraordinary crises. A century of bad ideas, big government, high taxes, deficit spending, sustained borrowing and easy money have blown up in what can now be seen to be a profound failure of political economy. Only Conservative ideas can extricate our country and the world from the present mess.

That insight is the key to getting through the difficult decisions which are ahead. These crises are an opportunity to fight together for the future of our country and to inspire our neighbours. We have one hope: that common-sense conservatism will defeat political radicalism in future as in the past. A deep unity of purpose is therefore not an option but an imperative if we are to make the most of a great opportunity to secure a generational change in the way we live.

Every Conservative will be a part of what is ahead but it is unavoidable that Conservatives will be on both sides of the big question we must settle. So we must learn quickly to disagree gracefully.

In this world of 24-hour news and always-on social media, mere devotion to a party line is untenable. The public wants and deserves thinking politicians who put the public interest first and can be seen to do so. It is reasonable to expect Conservative representatives to support a decision once it has been made, but the public will decide the question of our EU membership.

The truth about whether our country should remain a member of the European Union on the present or a renegotiated basis is uncertain. Diversity of opinion, if properly handled, is an opportunity to learn from one another, to reject fallacies and to more closely approach what is right. It is not by accident that our courts and our Parliament operate on an adversarial basis: robust yet civilised challenge produces better results than thoughtless obedience to authority.

In a decision of historic significance, constructive dissent is an obligation, not a problem. We will share in a process of discovery about our membership of the European Union. We will need one another’s challenge and debate if we are to refine our arguments and inform the public. We need one another if we are to find the best way forward.

Could we resolve to approach this process in a spirit of goodwill and inclination to learn from one another? Could we decide only to speak well of one another? Could we agree to honour one another by disagreeing respectfully, without fighting amongst ourselves, even in the glare of a media hungry for conflict?

We will certainly disagree, but we must remain one Conservative Party united by our commitment to freedom, responsibility, enterprise, nation and family. Families do not exclude those members who disagree, but embrace diversity of opinion against all comers.

It is in that spirit we must discuss our membership of the European Union.

Conservatives in Parliament have no desire to return to the kind of entrenched division of a generation ago which was so destructive for our party and our country. Some clearly have an interest in talking this up but, under David Cameron, there is absolutely no need to do so.  The Prime Minister agrees that we need a new relationship with our European partners, based on “trade and cooperation” rather than integration into a superstate.  He agrees with the principle that national parliaments are the true source of democracy and legitimacy in the EU. On human rights, he wants to see “British judges making decisions in British courts, and the British Parliament being accountable to the British people”.  He himself proposed a renegotiation along these lines, and then a referendum.

So there will be no repeat performance of the 1990s.  When the issue at stake is so substantial, today’s Conservative Party knows it is in vain to demand that people of integrity and intelligence must sacrifice both on the altar of slavish loyalty. But that does not mean we don’t play as a team on most issues – and today’s Conservative Party is a formidable team.

That is the crux of the matter: on the European Union question, a large number of Conservatives will be on each side of the question. If we are to achieve the necessary long-term unity, we will require an unprecedented openness to critical discussion among friends.

As the world changes and we navigate deep crises, we need a new perspective on constructive dissent. Respectful disagreement is an opportunity to learn and grow, to make better decisions. As the old hierarchies of centralised control and obedience give way to a more networked and freer world, we will look hopelessly out of date if every material difference of opinion is reduced to a titanic struggle for authority in which the weak must be crushed.

We can and must learn to disagree gracefully, to make better decisions as we strive towards unity of purpose not the impossible, the degrading, the dehumanising old fiction of unanimity of thought. The moment to do so is now.