Voters in Nova Scotia may be going to the polls sooner than expected, possibly as early as this fall.

There's growing speculation Premier Stephen McNeil is poised to call a snap election.

The party has balanced the provincial budget, a key election promise, but that surplus is razor thin and risks dropping back into deficit if a gamble to keep health spending in check fails. Tentative agreements with the major public sector unions are also in jeopardy now that two key union leaders who agreed to those deals are gone.

Summer is usually the time provincial politicians gear back their schedules and hit the barbecue circuit, but the whiff of a possible election mingled in the smoke has all three parties in the House of Assembly gearing up, just in case.

Candidates before Labour Day

Liberal MLAs and constituency associations without sitting members have been advised they need to have candidates nominated in all 51 electoral districts by Labour Day.

The average length between elections in Nova Scotia has been 3½ years since 1960. If McNeil holds to that pattern, the next provincial election would be April.

However, the Canadian Constitution and the Nova Scotia House of Assembly Act allow governments to hang onto power for up to five years.

McNeil won't rule out fall vote

But McNeil, who decides along with his closest political advisers the next election date, refuses to rule out an early election call.

He and other Liberals are keenly aware his predecessor, Darrell Dexter, might have maintained power had he not waited until the fall of 2013 to drop the writ.

Premier Darrell Dexter addresses supporters after his defeat in the provincial election in Halifax on Oct. 8, 2013. (The Canadian Press)

Polling by Corporate Research Associates tends to support that assertion.

In May 2012, just weeks before the NDP's third anniversary as government, New Democrats were maintaining their first place standing in party popularity. The substantial lead the party had enjoyed over its political rivals until then had eroded but it was still the party who would capture the majority of votes.

After that, the Liberals led in the polls until election day on Oct. 8, 2013.

Buchanan capitalized on 3-year mandates

Early election calls served former Progressive Conservative Premier John Buchanan well.

He won back-to-back majority mandates in 1981 and 1984.

Both times, his government served just three years before calling it quits and seeking a new mandate.

Provincial Conservative Leader Jamie Baillie will seek a campaign issue that strikes a chord with the voting public. (CBC)

What McNeil and his campaign team have to weigh in the weeks to come is whether a snap election call might seem too politically cynical and cost them votes, or whether, as Dexter learned in the last vote, waiting longer is worse.

Pros/Cons

Some other factors that may play into that decision:

Can the McNeil government keep the balanced budget it just passed in balance? The razor-thin surplus is predicated, in large part, on keeping health spending at 2014 levels. An early call would precede a crucial December fiscal update that could confirm the province is in deficit not surplus.

Union unrest. None of the major union locals representing thousands of public sector employees has signed a new contract with the province, despite tentative agreements. Two of the most powerful unions, the NSGEU and NSTU, will have new leaders, neither duty bound to live up to prior commitments. Job action or a deteriorating labour climate may convince the Liberals to enact Bill 148 and trigger an election on the issue.

Lacklustre opposition. Opposition Leader Jamie Baillie and recently elected NDP Leader Gary Burrill still haven't found widespread support. Each is looking for an issue that will provide the traction necessary to seriously challenge the Liberals. McNeil's promise to provide every Nova Scotian with a family doctor may be it. Allowing that issue to simmer may give the opposition the time it needs to win support.

It will be crucial for provincial NDP Leader Gary Burrill to win a seat if a fall election is called. (James Hutt)