For a party that has lost four straight provincial elections, the Progressive Conservatives are heading toward the 2018 campaign with plenty of enthusiasm and optimism.

Since Patrick Brown became leader in 2015, the PCs have maintained a solid advantage in the polls over unpopular Premier Kathleen Wynne and her Liberal government. They have lots of money in the campaign kitty, have signed up about 126,000 members, and have nominated more candidates than either the Liberals or the NDP.

But as the party holds its major pre-election convention on Saturday in Toronto, a deep-seated nagging worry lingers for the PC braintrust. They know they party has led in the polls ahead of previous elections, and still managed to lose. Can it happen again?

There are already some indications their lead may be dwindling to something far less than comfortable. While this review by CBC polling analyst Eric Grenier puts the PCs an average of 10 percentage points ahead of the Liberals, the trend in several polls shows the gap narrowing in recent months.

The most worrisome polls for the PCs are those by Campaign Research Inc., which can hardly be dismissed as a Liberal front group: it's led by Richard Ciano, former president of the Ontario PC Party, and Nick Kouvalis, past campaign manager for such right-of-centre politicians as Rob Ford, John Tory, Kellie Leitch and Christy Clark.

Ball hockey kitchener patrick brown

Ontario PC leader Patrick Brown joined in a pickup game of street hockey in Kitchener last summer. (Kate Bueckert/CBC)

Back in January, Campaign Research's polling gave the PCs a 22-point lead over the Liberals. This month, the lead was just three points. (Full data here.)  

The firm's CEO, Eli Yufest, relates the drop in Brown's approval rating — in particular among female voters — to recent attack ads by union-funded interest groups questioning where the PC leader stands. With the PCs struggling to get the public interested in Brown, his opponents have stepped into the void and branded him as a flip-flopper, said Yufest in an interview Thursday.

Another reason that Brown's and the PCs' numbers are flagging, according to Yufest: they've failed to present any policies that have excited voters. 

"If I was counselling the PCs ... I would probably suggest that they consider bold policy announcements to help raise their profile and give a reason to the electorate to vote for them," he said.

Brown has indicated a few Liberal policies that he opposes, such as the cap-and-trade system, which he has promised to dismantle, and his party said last week it would not hike the minimum wage to $15 until 2022, if elected.     

The PCs are hinting Brown will make some sort of policy announcement during his keynote speech to the convention on Saturday`afternoon. How bold it will be remains to be seen.

"This policy convention is going to be a celebration of the excitement we have in the party," Brown told reporters at Queen's Park earlier this week. 

Brown said the event at the Toronto Congress Centre will help the PCs "tell our story of where we want to take the province, how we're going to get Ontario back on track, how we're going to make it easier for Ontarians to make ends meet.  

"This weekend will give us a good sign of how his leadership stands and how effective he is at rallying all his troops around his own platform," said Geneviève Tellier, professor of political studies at the University of Ottawa. "​If you want to attract attention on the public scene, you need to offer some new initiatives or to present your platform. Until now, it's not very clear what the (Progressive) Conservatives want to present." 

The overarching concern for the PCs in this election appears to be to avoid making any campaign promises that blow up in their faces, as the pledge to cut 100,000 public sector jobs did to Tim Hudak in 2014, and  the vow to fund religious schools did to John Tory in 2007.

Patrick Brown

Saturday's PC policy convention 'is going to be a celebration of the excitement we have in the party,' said Patrick Brown. (Mike Crawley/CBC)

"Some of the foolish mistakes that my predecessors made could have been avoided if they took those items to the membership," said Brown in an interview last month on CBC Radio's Metro Morning

So, the party's grassroots developed the policies that will form the backbone of the PC platform. The 139 policies, revealed last month, were put to a vote of the membership. The party announced that every single one was approved.

That indicates either the PCs are really unified, or the policies are really uncontroversial.

"In those 139 ideas, we cover the gamut of what's bothering the people of Ontario," said veteran MPP Jim Wilson in an interview Thursday.

Wilson promised there's more to come. 

"You'll see some bold very conservative ideas come forward," said Wilson. "[Voters] want a change in government, but they want to know what they're getting. And in the next few months, we'll deliver policy so that people know what they're getting."