The Greeks knew it in Plato’s Nomoi (Laws), the Romans knew it in Renatus’ De Rae Militari (Military Matters), and Michael Corleone and Don Vito knew it.

And while your average Fine Gael and Fianna Fáil voters are unlikely to be in the habit of dusting down ancient Greek and Latin texts or flicking on The Godfather while having their dinner in the middle of the day, they will soon know it too.

Today, four-TD negotiating teams from each party will finalise their plans at internal meetings before sitting down at the table for the first real meeting of the confidence and supply renewal talks between Ireland’s warring houses on Thursday.

However, while party leaders Leo Varadkar and Micheál Martin are approaching the talks by trying to play the role of responsible leader due to the howling wolves of Brexit on Ireland’s doorstep, it is a safe bet that the internal party discussions are a far murkier affair.

Despite calls from both sides to extend the confidence and supply deal by two and one years respectively in the country’s interests, it is an open secret in both parties that an election is still near.

They may deny it publicly and commit “without any pre-conditions” to sitting down and breaking bread together as they discuss the first two and a half years of confidence and supply and how it could be improved.

But no one in Fine Gael’s or Fianna Fáil’s hierarchy is under any delusions that the smiles and handshakes are anything but the start of a strategic battle designed to prepare for an instant election the moment a real window of opportunity arises.

And voters shouldn’t be, either.

For Fine Gael, the tactic is straightforward: Push for a quick agreement on an unreasonably long-term deal which will further damage its opponent, while leaving open the option of catching Fianna Fáil off-guard with a snap election if there is any Brexit breakthrough early next year.

Since Taoiseach Leo Varadkar first suggested a deal extension to 2020 during his Italian mid-summer sojourn and his subsequent autumn letter to Mr Martin, the message has been repeated ad nauseum by the party faithful.

A new two-year confidence and supply deal, they say, would give the country stability throughout the Brexit negotiations, a view further underlined by Mr Varadkar on Sunday when he said that “it would be in the country’s advantage to have certainty”.

It may sound reasonable, and in many ways it is.

But Fine Gael will also be well aware that Fianna Fáil is highly unlikely to agree to a two-year extension that will make its own attempts to block off the growth of Sinn Féin into the opposition gap more difficult, meaning the olive branch is almost certain to be rejected.

Such a scenario would give Mr Varadkar ample cover to call a ‘forced’ snap election he will claim is of the opposition’s making the moment a Brexit breakthrough appears, thereby resolving the party’s still wafer-thin Dáil support and taking advantage of the recent giveaway election budget at the same time.

Fianna Fáil’s tactic is similarly doubled-handed, but has an added element thrown into the mix, which is key to how the entire process plays out: Drag the talks through the mud of every slip-up and controversy of the first two and a half years of confidence and supply before only then signing up to a shorter-term renewal once voters have been reminded of what life under Fine Gael involves.

Unlike Fine Gael’s two-year extension proposal, Fianna Fáil sources have indicated that a one-year deal is as far as they will stretch — giving the same reason of stability during the Brexit crisis to explain why.

The length of time involved is meant to allow Ireland to overcome the Brexit crisis hurdle while not forcing Fianna Fáil to sign up to a deal any longer than absolutely necessary.

However, like Fine Gael, Fianna Fáil eyes are just as firmly on an earlier timeline than official comments suggest.

Crucial to Fianna Fáil’s approach to the confidence and supply talks will be a detailed review of the existing confidence and supply deal, which will highlight problems with housing and health and Dáil debates, which are unlikely to show the Government in a positive light.

And the party’s negotiators will be fully aware of the need to make hay with these issues in drawn-out discussions over the coming weeks, giving Mr Martin ample ammunition to fire in the likely event any eventual agreement isn’t worth the paper it is written on.

Over the coming days and weeks, you can expect Fine Gael and Fianna Fáil to emphasise the need for stability in Ireland at the time of Brexit and to forget about an election any time soon.

You can even believe some of it.

But don’t be fooled into thinking the prolonged discussions, or even any potential one or two year confidence and supply deal extension, mean a lengthy ceasefire is set to occur.

Si vis pacem, para bellum. If you want peace, prepare for war.