The Supreme Court of Canada will hear a case that pits the federal Conservatives against Elections Canada over advertising expenses.
The justices have granted the Tories leave to appeal in the so-called in-out scheme.
As usual, the court gave no reasons for its decision.
The Tories argue that shuffling advertising money between national and local campaigns is a common practice and legal.
The elections watchdog maintains the scheme allowed the national party to exceed its spending limit by permitting local candidates to claim rebates on expenses they hadn't actually incurred.
The Federal Court sided with the Conservatives but the Federal Court of Appeal overturned that in favour of Elections Canada.