But there will also be important negotiations over the public airwaves. Parliamentary, party and public audiences will all have a significant stake and influence on the outcome.
Jonathan Powell told the BBC election programme that Nick Clegg gets to choose his dancing partners, and has chosen to take the first dance with David Cameron. The Conservative party is currently agitating at all levels - from parliament to the grassroots - to make sure there is no substantial agreement, beyond seeking passive LibDem support of a minority government. If Cameron takes that view, then it could yet reopen the door to Labour. (The Tory grassroots assume that they can have a minority government on this basis, but do not have a strategy to secure one, other than staring Nick Clegg down while refusing to negotiate).
Since Liberal Democrats are very keen on transparency in public politics, Labour should therefore make a very public statement of what its proposals for a common political reform platform would be, so as to bring as much public engagement as possible in what is being debated and negotiated on all sides.
What might this achieve?
Firstly, it would be designed to create a progressive opportunity to create a reforming alternative to a Conservative minority government.
Secondly, it should significantly raise the bar for the Conservatives in their engagement with the LibDems. Of course, if the Conservatives can offer as much or more than Labour on political reform, they ought to be in the box seat: it would be very reasonable for the LibDems to prefer to negotiate a similarly progressive package with the larger party.
Thirdly, it will ensure that there is transparency about the choice which not just Nick Clegg but the Liberal Democrat party as a whole (its MPs and the Federal Executive, and the broader membership) make. It would be for the LibDems to defend their political choice of an understanding which puts the Conservatives into government - based on their theory of the "mandate" - or alternatively an arrangement with Labour were discussions with the Tories to break down. Members of the parties concerned and the public will want to know what they were choosing between.
Fourthly, could this not also help to shape a reform agenda for the new House of Commons, whoever forms the government. We might well end up with a Tory-LibDem understanding - particuarly one which disappointed political reformers across all parties. If the LibDems were simply offering 'supply and confidence' (by abstaining on a budget, for example), there is no need for them to concede their own freedom of action of Parliamentary and political reform. There would be issues from a stronger Commons (which Tories might support), Lords reform and other political reform issues.
There is also an argument for Parliament being involved earlier, being made by Graham Allen, Member of Parliament for Nottingham North, who said:
"The future of the UK should not be cooked up between three party leaders and their entourages if there is no overall winner. A newly elected Parliament, at the height of its political legitimacy, should be reconvened immediately after the General Election so that the issues and possibilities can be fully aired and any final proposals endorsed. The public elect a Parliament and as yet they are not allowed to directly elect their Prime Minister. It is Parliament that should send one of its members to the Queen to receive the seals of office. I've written accordingly to the House of Commons Speaker today, and I hope that Parliamentary colleages of all parties will join me in asking Parliament to meet without delay and seize this chance for an important role for Parliament rather than being satisfied with being silent battalions deployed by party leaders."