It is a measure of the times we live in that the announcement of the agreement by the leaders of Fine Gael and Fianna Fáil to bring proposals for coalition to their parties was the second, third or fourth item on news bulletins last night.

No need to say what came before it. Yet the agreement by Leo Varadkar and Micheál Martin yesterday – albeit only the latest of a series of slow steps towards the goal of a “grand” coalition – is a truly historic move, a testament to how much Irish politics has changed and is changing before our eyes.

Neither party likes it much; that is the truth. They can see the electoral pitfalls, like everyone else. Martin in particular will face some difficult battles with his party to secure its agreement, though he would not be promoting something he did not believe could gain acceptance, and that means that Fianna Fáil expects to occupy the Taoiseach’s office first. Other key aspects of how the government will work, including at the very centre, must also have been agreed.

To many on the outside, this will appear as a last desperate bid by the old duopoly to keep their grip on power. Inside, it will look very different. It will look like a historic compromise, putting aside of age-old differences in the public interest. Never mind for a moment that those differences are less visible to the outside; to the two parties, those differences matter. Their leaders will present it as a political sacrifice – perhaps of their parties – in the public interest. Take them at their word if you like, or don’t. Either way, my guess is they will be judged on their deeds, and on their results in government.

All those who voted for “change” (whatever it meant to them) at the February election will complain that the FF-FG alliance is cheating the country of the change it demanded; that will be a cacophonous chorus indeed. Were they minded to take a broader view, the change-istas could equally interpret it as evidence of the revolution they have wrought on Irish politics in the 2020 election. The last redoubt of the old system has fallen.

Depending on where you stand, the substance of the agreement between the two parties is more important than the symbolism. What the new government does, after all, is less important than who is in it.

‘Substantial change’

There is little to go on, ahead of the presentation of the agreed principles to the respective parliamentary parties today. There will be fine words about a new approach – “a very substantial change”, according to one person involved – to health and housing, to climate action, and “a new agenda for public service”.

It identifies a number of “missions” for the next government, and promises a “new social contract”.

It will, in the words of another person involved in the process, be “more left-wing than the Sinn Féin manifesto”, but will contain little by way of specifics about how to achieve its goals – “or how to pay for them”, says another source.

This is partly because that minor detail has yet to be figured out. But it is also designed to leave room for the three smaller parties – the Greens, Social Democrats and Labour – to shape the eventual detailed programme, if they can be persuaded to join the talks. Though there is little expectation in Fine Gael and Fianna Fáil that they will.

Instead, the two old parties are likely to find themselves explaining why they continue to exclude Sinn Féin from a government that draws on so many of that party’s policies. Fianna Fáil and Fine Gael will not bend on that, though. It means that if they are to do this thing, they will likely do it alone.