The ultimate policy wonk is in his element. The Green Party negotiators wanted detail so Fine Gael rolled out Richard Bruton.
Almost 10 years to the day since his failed leadership heave, the Fine Gael minister is still centre stage and taking an increasingly prominent role in the talks with the Greens and Fianna Fáil.
He was brought in three weeks ago to deal with climate change. A participant in the talks said Bruton had a tour de force this week on transport, energy and emissions reduction policies.
Even the man of minutiae became frustrated by the Green idealists. The mild-mannered Bruton turned around in the talks and politely told them it was time to "get real".
The layers to the Greens' negotiating process, with large numbers of politicians and activists involved and reference back to groups, is causing impatience.
The most frequent line-up of TDs Catherine Martin, Neasa Hourigan, Roderic O'Gorman and Marc Ó Cathasaigh, and Senator Pippa Hackett tends to be supplemented by other TDs, senators, councillors and activists.
Fianna Fáil has brought Jack Chambers in as a substitute with a good grasp on climate and health policies.
"There has never been any momentum in these talks. Fianna Fáil would have had the deal done weeks ago," a negotiator says.
"For them, it's government or nothing. Fine Gael is letting their current popularity go to their heads but there will be a point at which the mood turns.
"It's hard to see how the Greens won't agree to a deal after being in there for four weeks. There is no read on the members though."
The high bar of getting two-thirds of Green Party members to sign off on any deal is a big demand and it's making the leadership nervous about getting items set in stone and driving a hard bargain.
The Greens will have a significant batch of policy wins to point to when they emerge.
The energy section of the Programme for Government is viewed as ambitious, pragmatic and achievable. The party's proposals on retrofitting of the housing stock is being fully taken on board, providing a stimulus for construction.
The National Development Plan will be reviewed with greater allocations for footpaths and cycle lanes, although there are doubts over the ability of councils to spend the money fast enough.
The ending of direct provision is still viewed as aspirational in the short term, but what's likely to emerge are reforms to the asylum seeker process to speed up applications for refugee status.
Leo Varadkar's defence of the direct provision system this week didn't go down well.
The contentious 7pc reduction in carbon emissions remains the big sticking point.
Notably, Fine Gael and Fianna Fáil are not quibbling on the figure. It will become an EU-wide target anyway. How it will be achieved is the issue.
The Greens made a last-minute hard push on agriculture emissions this week. Among their demands were higher reductions in the national herd and more dramatic targets for organic farming and the use of organic fertiliser.
After farming was mainly left out of the climate action plan, Fine Gael and Fianna Fáil have agreed agriculture will have to make a contribution to tackling climate change.
However, the larger parties want to link those changes to incentives from the reform of the Common Agricultural Policy. And there is also debate over exemptions for biogenic methane, largely created by cows belching, from inclusion in greenhouse gas emissions.
EU leaders will agree later in the year on continent-wide emissions reductions with a budget attached for troublesome sectors.
Eastern European countries will be compensated for winding down their fossil fuel industries and Ireland will pitch for assistance in agriculture.
Aside of CAP reforms, the contribution from farming may well be back-loaded to the latter part of the decade.
The parties are also agreed on the need for bringing the public along with them on climate issues, like increased carbon taxes, to avoid a repeat of the water charges fiasco.
Expect a public information campaign on saving the planet as 'citizen engagement' becomes the buzzword.
Collective cocooning in the talks for four weeks doesn't seem to have improved relations all that much.
Fianna Fáil's Michael McGrath has repeatedly mentioned deadlines for completion of the talks. The move is seen as a subtle check on Fine Gael's commitment to the talks succeeding.
Fine Gael remains in power until a new government is formed and its poll performance during the Covid-19 crisis makes a second general election an attractive option.
The Greens are still deeply suspicious of Fine Gael, particularly on housing.
The role of the Land Development Agency (LDA) will be amended to make it focus more on providing public housing.
Francis Noel Duffy, the Green TD and husband of Catherine Martin, is said to fume whenever there is any mention of "developers" or "commercial remits".
It's viewed as a sign of Greens' sensitivity to their left flank and Sinn Féin accusations that the LDA is a new form of Nama lining up public land for private development.
"It's a small but telling example of how exposed they will feel to their left from the Shinners if they go into government. The Greens will always be looking over their shoulders," a source said.
Fianna Fáil's red-line issue is fast becoming the increase in the pension age to 67.
Micheál Martin promised to reverse the proposal which flared up during the general election campaign and is digging in.
Fine Gael is retorting by saying the cost will simply mean other social welfare initiatives, like increasing benefits by €5 per annum, won't happen.
Fine Gael is also insistent on the budget deficit being tackled by 2023. However, the parties agree the economy should have recovered by that point, so growth in tax revenue should ensure the books balance out.
Down to the wire, the final bones of contention where compromise will be required is the detail of the 7pc emissions reduction, the pension age, direct provision and the deficit reduction.
"The next 48 hours is key. It's down to the hotspots now," a source in the talks said.
Fine Gael and Fianna Fáil are worlds apart from the Greens culturally, which has an internal power struggle going on between party leader Eamon Ryan and deputy leader Catherine Martin, who heads up their negotiations.
"If she agrees to the document, how does she not recommend it to the members," a participant says.
It still doesn't guarantee the Greens' grassroots are on board. The back-up plan is returning to the Independents and maybe getting support from the Labour Party for some sort of non-blocking voting pact. It's a long shot.
The Greens' membership rejecting it would have massive repercussions, with a second general election the most likely outcome.
Fianna Fáil is in a more invidious position. Micheál Martin can't possibly lead the party into another election.
Leo Varadkar and Fine Gael would fancy the chance of being the party of stability and fiscal rectitude in the wake of the leadership shown in the coronavirus crisis.
Sinn Féin and Mary Lou McDonald would await a left-right ideological battle with Fine Gael.
"I'm not sure the Greens' members realise it but they hold a lot of people's political destinies in their hands," a source in the talks said.