Of the 11 federal ridings in Nova Scotia, pundits say the one to watch on election night will be Central Nova, the Conservative stronghold that is being relinquished by high-profile Justice Minister Peter MacKay.

The riding's electoral fate will be under close scrutiny as the polls close across the Maritimes because it will offer an early glimpse of how voters have judged Stephen Harper's nine years in power.

MacKay has held the riding since 1997. His father Elmer held the seat from 1971 until 1993, except in 1983-84 when he stepped aside to let Brian Mulroney contest the seat in a byelection.

But this Tory bastion will be in play during the election campaign, says David Johnson, political science professor at Cape Breton University in Sydney, N.S.

"The MacKay family has owned that riding," he says. "Now that Peter MacKay has moved on, it's much more vulnerable, especially if the overall Conservative vote share drops."

One incumbent

With three of Nova Scotia's four Conservative incumbents stepping down from federal politics, the party's electoral fortunes are looking grim, says Jim Bickerton, a political science professor at St. Francis Xavier University in Antigonish, N.S., which is in MacKay's riding.

"The Conservatives are in big trouble here," he says. "It's hard to imagine that after two years of being so low in the polls that the Conservatives can suddenly turn it around in the campaign."

The only Conservative seeking re-election in Nova Scotia is Scott Armstrong, whose riding is next to MacKay's. He will face a stiff challenge from Liberal candidate Bill Casey, who once served in the Tory caucus with MacKay.

Casey was expelled from the Tory ranks in 2007 when he voted against the federal budget, saying it would hurt Nova Scotia's oil and gas industry.

Bill Casey's cult-like status

His decision to stand up to Harper earned him cult-like status in the province. In 2008, he won the riding as an Independent, taking almost 70 per cent of the votes.

"He's a local hero who's coming back into the scene," says Bickerton. "I'd say Armstrong is in for a big fight to hold on to his seat."

Aside from MacKay, Tory MPs Gerald Keddy and Greg Kerr are also stepping down.

Keddy has held a riding on Nova Scotia's south shore since 1997, where the New Democrats have been the main challengers since 2006. Kerr has held West Nova since 2006, repeatedly fending off challenges from former Liberal cabinet minister Robert Thibault.

The departures don't reflect well on the Tories, says Rick Emberley, senior counsel for MQO Research in Halifax.

"People sense something in that, even if they're over-analysing it," he says.

Liberals and NDP looking strong

With the New Democrats recent surge in the polls, talk of a Liberal sweep in Nova Scotia has abated. The NDP has fared well in previous elections in Nova Scotia, where Atlantic Canada's first provincial NDP government was elected in 2009 for one term.

Support for the federal NDP peaked in 1997 when the party won six seats, including the two traditionally Liberal seats in Cape Breton.

Bickerton says the NDP's three seats in and around Halifax are considered safe, as are the Liberals' four seats, mainly because all seven races will feature well-known incumbents.

"Some seats are just not in play," says Bickerton. "Whether the Conservatives can save some of their bacon is the main story line."

Johnson agrees, suggesting the two Liberal seats in Cape Breton are the safest in the country.

"The polling numbers do show a softening of Liberal support. (However), Liberal support would really have to go soft for them to lose the ridings that they currently hold."