The constitution of any politically mature country should include provision for some body or process that reflects/captures the public will. In Britain we've had such a body for about seven hundred years – the House of Commons.
In no successful constitution whatever, in any mature developed society, anywhere in the world, is it true that all processes/bodies reflect/capture the public will. For example, in Britain we do not hold public elections for our judges, policemen, monarch, civil servants, or heads of regulatory authorities (e.g. Ofwat, the FSA). Most phases of most legislation in the UK do not involve elected officials. Legislation is, overwhelmingly, devised by unelected officials, analysed by unelected bureaucrats and consultants, and rejected at numerous stages by unelected bureaucrats. Any suggestion that it is inappropriate for anyone unelected to be involved in the process of devising or approving legislation is laughably ignorant of the way the legislative process actually works in all mature developed societies.
Since it is no part of the concept of Parliamentary democracy that only elected officials should scrutinise, oversee and accept-or-reject legislation – otherwise there would be no democracy in the world (and never will be one) – in thinking about how to devise the process of legislation in a constitution, no-one should accept the wrong-headed and entirely unworldly notion that to be legitimate, every step in the process must be elected. The democratic case is that there should be input from the democratic will, not that the democratic will should be the only input.
Instead, our startpoint should be: What is the overall goal of our constitution? I answer: the promotion of ordered liberty, where order is understood as being in contrast to chaos (order is not a matter of degree – there is simply either order or chaos; the only question of degree is the issue of the degree risk of order collapsing) and liberty is understood as that freedom of action which human beings possess inately, through their ownership of themselves (we are not, by nature, slaves).
Order is threatened by the sinfulness of Man. We have rulers principally to maintain and enforce order, by restricting unordered liberty. Ordered liberty (that maximum degree of liberty consistent with a low risk to order) is threatened by the sinfulness of rulers. Both order and liberty are threatened by democracy, which, untamed, tends naturally to create a volatile tyranny of the majority. The purpose of a constitution is (a) to restrict rulers from unnecessary encroachments upon liberty whilst granting them adequate scope to achieve order; and (b) to tame and direct democracy so as to get the most from its virtues (especially the orderly acceptance of change) and the least from its vices (the ignorance of the voters, the intemperance of their opinions, and the instability of their preferences).
A constitution is not simply a document or a set of written rules. A constitution is the outworking in practice of the traditions, beliefs and disciplines of a country's ruling elites (multiple elites – intellectual, religious, military, financial, courtly - in tension and interplay with one another).
Ordered liberty thus has, as its natural enemies, the authoritarian dictator and the mob, and as its natural friends the constitution and the elites of which that constitution is the expression and defence.
Hence for any democracy to flourish, there must be checks and balances upon the democratic will that tame and direct it. In Britain, we can identify four classes of such check. These are (in order): the bureaucrats (including at European and QUANGO level); the House of Lords; the Monarchy; and the Judiciary. The central purpose of the House of Lords is to be a non-democratic check upon the democratic will, so as to limit the ability of authoritarian rulers to drive through their projects into legislation and to limit the ability of the mob to give vent to its vices.
Thus, to suggest electing the House of Lords is absurd. It is as if one proposed a system for checking the truth of what is written in newspapers, and one's mechanism for checking was to look in newspapers. One only provides a check on the democratic process by going outside democracy – democracy cannot be checked by itself!
Now, of course, the House of Lords is not the only check on democracy – we still have the bureaucrats, the Monarch and the Judiciary. It is unclear to me how sustainable it would be to retain a constitutional monarchy in the legislative process if one abandoned the concept of an unelected Upper Chamber – if unelected Lords are unacceptable, an unelected sovereign approving / rejecting legislation would surely be more so. But we could, of course, get along without an Upper Chamber or a constitutional Monarch (doubtless we'd retain a ritual monarch for those folk into celebrity culture – I'll pass, myself). Countries can get by with one elected chamber, and very powerful bureaucracy and judges. They tend to require, for stability, rather less liberty and rather less scope for democratic change than is provided by a bicameral system with an unelected Upper Chamber and a constitutional Monarchy. They also (partly as a consequence of the reduced liberty and reduced scope for democratic action) tend to degenerate into revolution every few generations. But they work well enough, after their own fashion – some people even describe them as "modern".
My own preference, though, is for greater liberty, defended by an unelected Upper Chamber and a constitutional Monarch, greater scope for democratic change (with democracy tamed and directed fruitfully by the key unelected elements in the constitution), and so less frequent revolutions. So my preference would be for keeping an unelected Upper Chamber.
But either way – whether we have an unelected Upper Chamber, or abolish the Upper Chamber altogether – there is no case whatever for having an elected Upper Chamber. What conceivable function could that serve? We already have an elected chamber – the Commons. Why would we want another? (And if we did want another, why just one other? If it is so wonderful having extra chambers for their own sake – what with the public being so keen on elected politicians, why not have five?)
There is zero public appetite for this. The main criticism of the House of Lords is cronyism – that appointments to it are too controlled by the Prime Minister. Thus, the main problem people perceive with the House of Lords is that it is too democratically-influenced, with its membership set via the democratically-elected chamber. The proper direction of reform to the House of Lords should be making it less democratically-influenced, not more, so that it can properly execute its key function of taming democracy. If having an unelected House of Lords is no longer sustainable, just abolish it and embrace our post-constitutional-monarchy fate. The last thing we want is an elected Second Chamber.