Two things today convince me that our democracy is deeply flawed. First, Parliament's decision that the referendum on the Alternative Vote will be binding, and will be won by a simple majority. Second, the government's decision to scrap forestry sales.

I've been boning up, prior to writing a short primer on the subject, on Public Choice economics. This is the idea that you can apply economic tools to the workings of government. It is clear that in majority voting systems, the majority can exploit the minority. But James Buchanan, who got a Nobel Prize for it, says it's worse than that. He shows how the self-interest of politicians, officials and interest groups, and the bargaining between them, can lead to minority interests benefiting at the expense of the rest of us. He says that for some important issues we should demand more than a majority for the decision to be made. And for deciding the rules of that process – the constitution, if you like – we should demand complete unanimity, so nobody risks being subsequently exploited.

Making a referendum binding for the first time in the UK's history is, let's face it, a constitutional change of some magnitude. As is changing the voting system itself. Whether you support AV or not (no parties actually proposed it in their manifestos), it seems reasonable that it should require a large measure of public support to happen. Few people know much about the subject, so in some areas the turnout could be miniscule: it could be a constitutional change chosen by a small minority – an interested, informed minority – that could have major consequences for the rest. Likewise, the decision to make the referendum binding is made not by the people but by a simple majority in Parliament, a body whose democratic credentials are rather tarnished right now. If this is allowed to stand, who knows what other binding referendums might be proposed in future? Maybe having more referendums is no bad thing – Switzerland seems to get on fine with it. But horse-trading in Parliament is a bad way of making constitutional change.

And the forests? It just shows how decision-making is dominated by interest groups. I cannot believe for a moment that all the celebrities who wrote to the Times and got the campaign going understand one iota of the actual policy, or have the faintest idea of what Forestry Commission land actually comprises and how well or badly it is managed. We really are at the mercy of minorities. If we are forced to accept their opinions in binding referendums too, then our democracy is really sunk.