Just as the talks about new rules on the funding of political parties broke down last week, the murky business in Falkirk reminded us why reform was so necessary. The two largest parties in this country are hollowed-out, broken-down shells, in which the selection of candidates to be MPs is open to manipulation, and the funding of which means conflicts of interest are inevitable. It is no wonder that politics, held in low esteem at the best of times, is now so despised.
Unfortunately, cross-party agreement on funding is in the short-term interest of neither the Conservative nor the Labour party. Despite the Prime Minister's obvious glee at Ed Miliband's discomfiture about his main union donor influencing the next intake of Labour MPs, the Tories also depend on donors who have an interest in government policy.
The Independent on Sunday has long been clear about the essentials of a new settlement. The starting point is that there should be no increase in taxpayer funding of political parties. Government parties employ special advisers, who may engage in party-political activity, on the public payroll, and other parties receive funds known as Short money (after Ted Short, the Labour leader of the House of Commons in the 1970s) to support their parliamentary activities. Asking voters to pay more for something they hold in contempt is not the best way to start to rebuild trust in politics.
The second point is that there should be a limit on the annual amount that any individual or organisation can donate to a party. This is where the party-political manoeuvring begins. Labour wants to set the limit as low as possible, because the Tories receive more money from rich individuals. The Conservatives, meanwhile, want trade-union donations to be treated as if coming from a single organisation. Labour's response has always been that the money from unions comes from the political levy paid by millions of trade unionists.
The Falkirk imbroglio offers a chance for Mr Miliband to break this impasse. He should propose a change in the law so that the political levy from trade unionists goes directly to the party concerned, rather than being granted at the say-so of the union's leadership.
But even cutting that Gordian knot would not be enough to start to repair the bond of trust in politicians. The selection of candidates needs to be broken open, as this is the tiny, constricted point of entry to the House of Commons in most seats, which are the safe property of one or other of the two large parties. One of the most disappointing retreats from democratic principle, a collusion in this case between Mr Cameron and Nick Clegg, was the dropping of their promise to hold primary elections to choose candidates in safe seats. The Coalition Agreement said: "We will fund 200 all-postal primaries over this Parliament, targeted at seats which have not changed hands for many years." It has been quietly shelved.
Mr Cameron is thought to believe choosing would-be MPs that way makes it impossible to maintain party discipline, having learned from his experience of Sarah Wollaston, the independent-minded Tory MP for Totnes, who was selected in an open primary before the 2010 poll. For the rest of us, Ms Wollaston is a shining example of the kind of brave, knowledgeable MP of whom we would like to see more.
This is too important an issue for Mr Cameron and Mr Miliband (and Mr Clegg) to play for what they see as their short-term advantage. The health of our democracy requires new rules to limit the buying of influence and to open up the narrow points of entry to the Commons.