Four federal byelections today will test just how much of a comeback the Liberals have staged under the leadership of Justin Trudeau.
While they're not necessarily harbingers of what's to come in next year's general election, the two Toronto ridings and two Alberta ridings up for grabs will send some important signals.
The Liberals' all-out effort to steal the downtown Toronto riding of Trinity-Spadina from the NDP will give some indication about who's got the edge in the battle for opposition supremacy.
Trinity-Spadina was held by NDP MP Olivia Chow until she stepped aside to join the Toronto mayoral race in March.
Chow held the riding from 2006 to 2014.
In the June 12 provincial election, the riding saw longtime NDP MPP Rosario Marchese lose to Liberal Han Dong.
Federally, Toronto city council stalwart Adam Vaughan is running for the Liberals, while the son of two former city councillors, Joe Cressy, is running for the NDP.
The Conservative attempt to snatch Toronto's Scarborough-Agincourt from the Liberals may also provide evidence of whether the party's attacks on Trudeau and his support for marijuana
legalization are effective.
Liberal MP Jim Karygiannis stepped down so he could run for city uncillor in the municipal election.
How the Liberals perform in Fort McMurray-Athabasca, Alberta's oil sands heartland, will signal whether there's signs of life for the Grits in what has been a political wasteland.
The Conservatives are expected to easily hold onto the other Alberta riding, Macleod.