DUBLIN — Ireland’s political turmoil deepened on Friday, pushing the minority government in Dublin toward collapse just weeks before it is set to play a central role in negotiations over Britain’s planned departure from the European Union.

The government of Prime Minister Leo Varadkar is able to remain in power in Ireland only with the support of the main opposition party that, on Friday, submitted a motion of no-confidence in his deputy prime minister — part an enduring dispute over her role in a policing scandal.

The move has consequences on two, interwoven fronts. First, it could lead to a snap election. And second, an election campaign would probably affect a European Union summit meeting in Brussels in mid-December, adding a further imponderable to the halting diplomacy over Brexit, as Britain’s withdrawal from the bloc is known.

The summit meeting is supposed to determine whether Britain has satisfied the other European Union members that negotiations have made sufficient progress to initiate parallel bargaining on a trade deal between London and the 27 remaining countries in the bloc.