The arguments for a proportional electoral system are familiar. In 2005, only a third of British MPs were elected by more than 50% of the votes in their constituencies.  In the other two-thirds, the majority of their constituents did not support their MP and may well be actively opposed to their policies. This is not even majoritarian democracy.

The current First Past the Post system massively under-represents minority parties, strengthens the Executive to the point of elective dictatorship and creates a sense of futility in large pockets of society – most notably the young and the poor.

The Lib Dem manifesto for the 2010 Election studiously avoided the terms PR and proportional representation. In his post on Our Kingdom, Nick Clegg says the electoral system “is bust” and claims:“If we want to ensure MPs don’t abuse their positions, we must abolish jobs for life in politics. Liberal Democrats will do that by introducing fair votes so every vote counts”.

Doesn’t this clear the way for a compromise on voting reform? The interview Nick Clegg gave to the Financial Times on 3rd May seems to confirm this when – with at the time the Labour support falling into third place – the Liberal Democrat leader said voting reform per se was “not a precondition” for negotiations with the Conservatives.

Our existing legislative system is seen by many voters today to have serious problems: it is felt to be variously unresponsive, unchanging, controlling, inflexible, elitist, corrupt – and above all, protectionist of Big Party power. Nick Clegg himself refers to this as the "Westminster stitch-up".

With his new-found popularity, Mr Clegg could challenge both the other party leaderships to say what they have against STV in particular. The Lib Dems have been careful about such a direct challenge thus far, but now they can’t afford to be.

STV removes the concept of the ‘safe seat’ forever. It will force backbench MPs in a multi-member constituency to consider the needs of large minorities, if only out of enlightened self-interest. It stands a chance of reducing Executive power while making more local people feel ‘connected to’ their representatives.

Stephen Tall on Liberal Democratic Voice admits that STV is the hardest system to sell to the public – because it requires the most fundamental reform. But fundamental reform is never easy; Nick Clegg has a duty to at least try. When people hear fluffy concepts like “fair votes” and “so that every vote counts” and not harder terms like proportionality and counting equally, voters smell the fudge. They want change but part of the change they want is honest conviction not preparations for comprise. By being more specific and outspoken the Lib Dems would not be making hostages to fortune, they would be making themselves more popular and effective.

John Ward blogs at The Slog.