Amid the frenzy over the already fierce battle between New Democrats and Liberals in Trinity-Spadina, it's easy to forget that another Toronto-area riding will be up for grabs when voters head to the polls on June 30.

Sharp-witted party strategists, however, are likely spending considerably more time fretting over the fate of Scarborough-Agincourt — and, more specifically, whether the Liberals' 25 years of incumbency had more to do with the particular incumbent than the colour of the banner he carried into battle.

That may well be why the very first stop on Liberal Leader Justin Trudeau's mini-tour of the Greater Toronto Area last week was the grand opening of duly nominated candidate Arnold Chan's campaign office.  

Now former MP Jim Karygiannis may never have been in the running for a caucus congeniality award, but he was one of the very few Scarborough-area Liberals to hold the thin red line during the Great GTA Meltdown of 2011, an achievement that almost certainly had more to do with his larger-than-life personality than lingering Liberal loyalty.

Support in Scarborough dropped in 2011

In the neighbouring riding of Scarborough Centre, Karygiannis's former caucus colleague John Cannis lost the seat he'd held for more than 15 years to Conservative contender Roxanne James, who had tried twice to oust him.

Meanwhile in Scarborough-Rouge River, the departure of longtime Liberal Derek Lee undoubtedly played a role in what was more than just a surprise victory for New Democrat rookie Rathika Sitsabaiesan.

It was an even more shocking defeat for Liberal candidate Ran Sarkar, who finished a distant third.

The New Democrats also managed to take Scarborough-Southwest, with Liberal incumbent Michelle Simson also dropping from first to third place, albeit by a considerably narrower margin, with all three main candidates pulling in between 29 and 35 per cent of the votes.

Even Karygiannis himself watched his margin of victory plunge by more than 10 percentage points — from a comfortable 57 per cent in 2008 to just 45 per cent in 2011.

Both the Conservative and New Democrat contenders in Scarborough-Agincourt saw an upswing in support.

Karygiannis legacy looms large

Karygiannis had what turned out to be, at least at the time, an unbeatable advantage: a local organization that could legitimately be described as a machine. 

In 2012, the Scarborough-Agincourt Liberal riding association pulled in a jaw-dropping $241,238 in donations. To put that number in perspective, that's the biggest one-year haul reported by any riding association for any party, anywhere in the country.

That puts it comfortably ahead of Jason Kenney's Calgary Southeast riding association, which ranks second in annual revenue with a comparatively modest take of $195,510.17.

Even more astonishing is the number of contributors: 763 in total, more than two-thirds of whom gave more than $200.

It's not clear whether Chan can count on those same donors handing over a similar amount to his campaign, or how many will hit the byelection hustings on his behalf without a gentle nudge from the man he hopes to succeed. 

But that nudge may not be forthcoming.

In fact, at this point, it's unclear whether Chan can even count on Karygiannis's vote.

Result reflects on Trudeau

During the pre-byelection nomination contest, Karygiannis endorsed a rival candidate — his former constituency assistant Nikos Mantas — who failed to secure the necessary support at the party-run poll (although the exact results weren't released, which leaves unanswered the question of how close a race it was).

Just this week, the unabashedly anti-abortion Karygiannis told Power & Politics host Evan Solomon that Trudeau's ham-handed approach to the issue would "definitely" hurt the party in future.

That could turn out to be a self-fulfilling prophecy in Scarborough-Agincourt at least. Karygiannis says he's now "liberated" to share his thoughts whenever the spirit moves him, without fear of caucus repercussions. (Though it's worth noting that he never seemed to let such concerns still his tongue when he was on the Hill.)

There's no sure way to know how many of his erstwhile constituents share Karygiannis's views on abortion or the newly hard-lined party policy on the subject.

Still, it's hard to see how those voters — who kept Karygiannis in office in 2011 — wouldn't take his comments into account, particularly if he were conspicuously absent from Chan's campaign.

If Scarborough-Agincourt falls to the Conservatives or the NDP on June 30, it would be seen, rightly or wrongly, as a stinging rebuke of Trudeau's leadership skills so far.

In that case, even an upset victory in Trinity-Spadina wouldn't be enough to save the Liberals from being seen as the biggest losers on the byelection night.