Vincent Cable

Politics needs fixing. Trust in politicians and politics is at an all time low. The public are, rightly, demanding change and the Liberal Democrats have led the way in calling for a series of measures – reform of the House of Lords and party funding, fixed term parliaments, enabling legislation for a referendum on electoral reform, to name but three – in a bid to restore faith in our political system.

In my view, one of the biggest institutional weaknesses in the government's management of the economy is the total lack of parliamentary involvement in the governmental allocation of funds, before a penny is spent. At present, tax is scrutinised in detail but spending choices are entirely a matter for the executive. There is of course the National Audit Office but their oversight of spending is limited, selective and retrospective.

Line by line approval of spending commitments (and cuts) would concentrate the minds of legislators in a way which is currently missing in the opaque processes of Whitehall.

Public spending is going to dominate the political agenda for the foreseeable future. Making the process open and transparent would go a long way to fixing politics and restoring the public's faith in the system.

Jo Swinson MP Photograph: Guardian

Jo Swinson

Involve people. The public's disengagement with politics is both a symptom and a cause of our broken politics. To break the vicious cycle, we need a radical shake-up of how the voting public can take part in democracy. It should no longer be just about casting a vote every couple of years, and leaving the rest up to those elected – fixing politics can't be left to the politicians. We must encourage much wider involvement, through a citizen's convention to recommend big changes to our political system.

We should build on the pioneering work of initiatives like theyworkforyou.com, to help people know and understand what is going on. The arcane Westminster culture that seeks to place barriers between MPs and the public must be challenged: why, in 2009, does the House of Commons still not allow clips of Parliament to be shown and shared on YouTube and other sites? We should implement the idea put forward by Parmjit Dhanda in his hustings for the Speakership, to let the public have a say over what gets discussed in Parliament, for example by voting on the subject of each week's topical debate.

Most of all, there should be a concerted effort from all involved in politics (and ideally also from the media) to encourage people to get involved. By harnessing people's genuine interest in political issues, we can reinvigorate our broken politics.

Norman Baker MP Photograph: Guardian

Norman Baker

We need to implement three key reforms. First, we need greater transparency. We must extend the scope of the Freedom of Information Act. That might prove unpopular with many MPs – only eight months ago, the government was trying to claim that MPs should be exempt from the act altogether – but it is absolutely necessary. We need to end the present culture which allows for far too many government exemptions, and we must increase the level of funding we give to the Information Commissioner.

Second, we need greater accountability. There are some significant changes that must be made to our parliamentary system. We need to change our archaic voting system so that it better represents what people really want, and reform the Lords, as the Lib Dems have been advocating for years. Key changes must be made inside Westminster as well. Some of the traditions that we cling to do nothing to improve accountability. I believe that if we are to have members of the House of Lords as Secretaries of State, they should be accountable for oral questions in the Commons. We must also address the government's lack of respect for Parliamentary Questions – for example, my research indicates that less than 20% of a random sample of questions asked of the prime minister receive any sort of meaningful response.

Third, we must ensure that anybody who spends public money is subject to transparent external audit. As far as MPs' expenses go, all of us must be prepared to accept the recommendations of Sir Christopher Kelly's report, whatever those may be. It won't be easy to cure the problems that have blighted our political system for so many years, but greater transparency and accountability will put us on the way towards regaining the public's confidence. Sunlight really is the best disinfectant.

John Curtice

The MPs' expenses row is but the latest in a long list of alleged political scandals that began when John Major's government became mired in sleaze. Each time the same remedy has been proposed – greater transparency and tighter regulation. So, for example, political parties and MPs have to report details of the donations they receive, which are published for all to see. Now a new body has been created to regulate MPs' finances, while full details of their claims are on the web.

Yet despite repeated applications of the remedy, scandals still erupt and trust is not restored. The problem with transparency is there is no guarantee the public will like what it sees. Who thought more highly of Tony Blair because we knew he raised money from wealthy businessmen? And the trouble with tighter regulation is that it creates more and more tripwires for MPs to fall over. Witness the difficulties that befell Peter Hain over his deputy leadership campaign.

MPs need to look at how they behave. Rarely do political opponents avoid the temptation to cast aspersions when a MP is alleged to have broken some rule. And so long as politicians constantly treat each other with suspicion, how can they possibly expect the rest of us to trust them?

The Guardian debate – "How can we fix politics? Is this the Liberal Democrats' hour?" – at the 2009 Liberal Democrat Party conference will take place on Monday 21 September at 1pm at the Royal Bath Hotel, with Vincent Cable, Jo Swinson, Norman Baker and John Curtice, chaired by Simon Hoggart