On the Seattle Sounders rivalry scale, the Vancouver Whitecaps most assuredly feature, but it's difficult to pin down exactly where; the vitriol is decidedly less than that directed towards the Sounders' neighbors to the south, while the Western Conference's elite sides such as the Los Angeles Galaxy and Real Salt Lake have proven to be far more frustrating opposition in the quest for the top of the league. Still, it's tough to set aside the history between these two clubs; Seattle and Vancouver have done battle at multiple levels throughout the modern history of North American soccer, from the NASL to the A-League to USL and into the present day. And for the first time in their short MLS history, the Whitecaps look to be a very difficult test for the Sounders.
Vancouver has thrived under new head coach Martin Rennie, building themselves from a porous defensive and consistently sputtering attacking side into a very competent team which has at its core a strong back line and a pair of dangerous strikers in Sebastien Le Toux and Eric Hassli. The end result is a team just one place behind the Sounders in the standings, a clear step below the elite but well clear of the stragglers in the bottom half of the Western Conference.
With a full complement of attacking players the Sounders will be a tough task for the Whitecaps to handle, but Vancouver's dangerous counter-attack will likewise pose a threat for Seattle. Though the Seattle-Portland rivalry may garner the majority of the headlines, this particular incarnation of the Cascadia rivalry may be the more important (at least this season.) If the Sounders newly reunited front-four is able to click, it could spell serious difficulty for Vancouver, but if Seattle's attack continues to sputter the mean back line of Vancouver may well hold things close enough for a persistent Whitecaps attack to fire the first salvo in this season's battle for the Cascadia Cup.