By Adrian Browne
BBC Wales political reporter
Much of the opposition from Plaid Cymru and Welsh Liberal Democrat party members is focussed on the prospects of sitting in cabinet with Conservatives.
John Redwood and Nick Bourne - 17 years apart
Many Plaid and Lib Dem members are horrified at "getting into bed" with the party of Margaret Thatcher and Tory ex-Welsh Secretary John Redwood.
Why do senior Plaid and Lib Dem figures believe they can work in government with Tories in Cardiff Bay?
One reason is that they are convinced the Welsh Conservatives have changed.
An influential Plaid Cymru AM told me that if it was still the party of Mrs Thatcher and Mr Redwood a rainbow coalition would be "impossible".
He maintained that the Welsh Conservative Party had transformed itself from being what he called a "negative opposition party" to one which was trying to make a genuine contribution to Welsh politics.
That view was supported by a Conservative who was active in the party throughout the Thatcher years and since.
But the experienced Tory believes the fact that the Welsh assembly does not have tax-raising powers helps the three parties to co-operate.
UK-style arguments over the merits of 'big government' or tax cutting are academic.
The Welsh Assembly Government receives its funding from the UK treasury based on a formula, and then decides how best to spend the cash.
The way the money is raised is therefore not a key issue in Cardiff Bay politics.
Tory AMs could be sitting around the cabinet table
Any reading of the Conservative, Liberal Democrat and Plaid Cymru assembly election manifestos shows plenty of overlaps on policy.
One Lib Dem insider told me that staff had their work cut out finding ways of criticising many Tory policies during the campaign because there was so much they agreed with.
The Liberal Democrat said due credit for that should go to the man who wrote the Tory manifesto, the Welsh Conservative policy director David Melding.
Combine this with the trust built up between the three parties, and their leaders, in opposition over the last few years and you begin to see how a joint administration could get off the ground.
The system of proportional representation for electing Assembly Members makes it difficult for one party to win a working majority.
Nevertheless, since Labour has won the largest share of the votes in Wales for the best part of a century it has gained more seats than any other party in the three assembly elections.
Working together appears to be a logical strategy for parties wanting to make the journey from opposition to government benches.
The Conservative assembly group leader Nick Bourne has called it "the only real way of breaking Labour's stranglehold in Wales".
Against the grain
Welsh politics has traditionally been tribal.
Regardless of policy, working with political opponents has gone against the grain for a very long time.
Yet the barriers have been breaking down in Welsh local government, where former opposition parties have increasingly been working with each other to boot Labour rulers onto opposition benches.
The Welsh assembly increasingly seems to be the next step for a new form of politics in Wales.
It is a big step, and if it does happen there will no doubt be some difficult moments over the next few years when Plaid and Lib Dems say to each other "remind me why we're working with them again".