The partnership agreed between Fianna Fáil and the SDLP could either make or break both parties.
As it stands, they have much in common. The SDLP was a strong political force in the late 1990s, with three MPs in Westminster, topping polls in Assembly elections and dominating local councils in Northern Ireland. Since then, they have been eclipsed by Sinn Fein and have lost much of their core vote.
Fianna Fáil’s dominance in the south is now a distant memory and it, too, has suffered at the hands of Sinn Fein, while also being squeezed by a resurgent Fine Gael.
Both Micheál Martin and the SDLP leader, Colm Eastwood, need to find a mechanism to make their respective parties politically relevant again. It is as yet unclear what the nature of the partnership will be, let alone whether it will have the desired effect.
Both FF and the SDLP say that a merger to create an all-island party is not currently envisaged, but Brexit has prompted republican calls for a referendum on Irish unity, after a majority in the North voted to remain in the EU.
It is 12 years since FF’s then leader, Bertie Ahern, established a party presence in Northern Ireland, but its defeat in the 2011 general election in the Republic put a halt to those plans. This partnership may be no more than an experiment in joint policy-making, or it could be a precursor to a merger. Whether or which, Irish politics just got more interesting.