This week’s Irish Times/Ipsos MRBI opinion poll allows a timely assessment of where the sometimes confused state of our politics is at and what that means for the likely composition of the next government.

There were three outstanding messages from the poll that signal what lies ahead. The first is that there will be an intense slugfest between the big two parties to gain the most seats, and then to lead the next government.

The surge in Leo Varadkar’s personal ratings cheered Fine Gaelers no end and amplified the now pretty constant clamour for a November election in the party (most of Leinster House talked about nothing else all week).

But Fine Gael’s number didn’t shift, and even if you would expect it to be dragged up a bit by the leader’s approval in the wake of a Brexit deal (it’s normally a leading indicator), the race is still pretty tight between Fine Gael and Fianna Fáil.

If Sinn Féin are in reality out of the coalition business, that hands more power and influence to the other players

That’s because on previous form – no guarantee to future performance, as they say, but persuasive nonetheless – Varadkar will need to be well ahead of Fianna Fáil when the general election is called if he’s going to be still ahead when the votes are counted.

The Fine Gael-Fianna Fáil battle will dominate the next election campaign but whoever wins will need the support of smaller parties to form a government. And it is often the smaller coalition partner that defines the policy stances of the government.

It’s not that there is no difference between Fine Gael and Fianna Fáil; there are differences of history, culture, character and inclination. But the record of the two parties in government suggests that they are both comfortable with centrist coalitions which lean either to the right or to the left.

So we must pay attention to the likely partners that the big two will be courting before and after the election. So the second thing about this week’s poll to note is the worsening position of Sinn Féin, and what that means for its likely availability for coalition duty.

Sinn Féin decline

At the last election, Sinn Féin ruled out coalition as a junior partner; that approach was changed by Mary Lou McDonald, who indicated that the party was now ready to embrace that option.

But the dreadful fortunes of her party since – continued in this week’s poll, which showed a 10-point decline in the last 12 months – have probably deprived McDonald of the political strength needed to carry out that plan. McDonald is unlikely to do a public U-turn and rule out government, though – most likely she will try to have her cake and eat it, being part of the conversation about government, but ultimately not involved in its resolution.

That might work. It might also be pretty transparent.

If Sinn Féin are in reality out of the coalition business, that hands more power and influence to the other players. Which brings us to the third important message from this week’s poll: the Greens.

The Greens will demand that lots of roads projects are cancelled and the funds diverted to public transport. Politicians love new roads

I think that the Greens may be about to benefit from one of the surges that small parties in Ireland periodically gain from. They went gangbusters at the local and European elections, but this week’s poll shows that they are on course to do much better. At 8 per cent nationally (13 per cent in Dublin, where many of the target seats are), the Greens are on the cusp of a real breakthrough.

If the Greens’ ascent in the polls continues, they can realistically target 10-12 per cent in the election. At 10-ish per cent, the Labour Party habitually won seat numbers in the late teens-early 20s.

Now the Labour Party had a fully operational national political organisation and councillors everywhere, while the Greens don’t. That’s why getting candidates into the field and before the voters in every constituency where they have a snowball’s chance of a seat is one of the top two priorities for the party, if it wants to translate public concern about climate change into the political clout to do something about it.

The second priority is figuring out how to translate Green policy priorities into the chunks of a programme for government that they can realistically negotiate with either Fine Gael or Fianna Fáil.

Diverting investment

The Greens know and admit privately that going carbon neutral by 2030 – as the Extinction Rebellion protestors demand – isn’t going to happen.

But they do know that they can divert investment to public transport to get people out of cars, promote new models of agriculture, shift the focus to renewable energy and make people’s homes more efficient – and all these things can be done using the enormous financial clout of government.

That’s why the Greens are likely to look for the Department of Public Expenditure in any new coalition. This thought, I understand, has already occurred to Green Party leader Eamon Ryan.

Ryan will need to keep the public on board – as the poll also demonstrates, the public may be convinced about climate change, but they’re queasy about paying to fix it. He will also have to drag the political system along.

But if he does a deal after the election with Labour – which Labour is pantingly keen for – Ryan will hold the key to the next government and he will be able to name his price.

One example: the Greens will demand that lots of roads projects are cancelled and the funds diverted to public transport. Politicians love new roads because their construction shows their constituents they are “delivering”. (See Varadkar and Michael Ring in Government Buildings this week announcing a new road from Westport to Turlough).

Could you live with the Greens’ requirements to cancel road projects, I asked one senior figure in one of the big parties this week.

He replied: “The Greens will get whatever they want.”