By voting to join forces over the weekend, the Alberta Progressive Conservative and Wildrose parties have increased their odds of defeating Rachel Notley's New Democrats. But lessons from the 2003 merger that created the federal Conservative Party should caution them against taking victory for granted — or thinking that one plus one will equal two.

At 95 per cent in favour of a merger that will create the United Conservative Party (UCP), the vote among the two parties' respective members was nearly unanimous. But the general voting population may not get on board in such big numbers, if the last merger of conservative forces is any guide.

In 2003, the federal Progressive Conservatives under Peter MacKay and the Canadian Alliance under Stephen Harper agreed to merge.

There are similarities between the two events. In both cases, the older conservative party — the PCs — was overtaken by an upstart, populist party created by disgruntled members from the older organization.

The Reform Party and, subsequently, the Canadian Alliance formed the Official Opposition in Ottawa after the 1997 and 2000 federal elections, just as Wildrose did after the 2012 and 2015 provincial votes. The federal PCs were decimated in 1993 and were on life support, just as the Alberta PCs were in the aftermath of the 2015 election that ended their 44-year run in office.

Lessons from the past

In their last election as individual parties in 2000, the PCs and Canadian Alliance combined for 38 per cent of the vote, just three points behind Jean Chrétien's Liberals. The Liberals benefited from the split on the right — the Canadian Alliance took 25.5 per cent and the PCs 12 per cent — to secure a majority government.

But in 2004, the Conservatives were unable to retain all the support of their two legacy parties. Their combined vote share fell by eight percentage points to 30 per cent.

In raw ballots cast, the Conservatives were down 824,000 votes. Though there would have been some exchanges with other parties as well, the net result was that about one in five Canadians who cast a ballot for the Canadian Alliance or PCs in 2000 either stayed home or went elsewhere in 2004.

Peter MacKay shakes hands with Stephen Harper after their announcement of the PC-Canadian Alliance merger on Oct. 16, 2003. (Jim Young/Reuters)

A post-election survey by Pollara found that while 88 per cent of people who voted for the Canadian Alliance in 2000 had cast a ballot for the Conservatives in 2004, just 68 per cent of PCs did. A tenth of PCs voted for the Liberals and another tenth did not vote.

Nevertheless, despite the drop in overall support the Conservatives benefited from no longer splitting their vote, winning 99 seats instead of the combined 78 seats the Canadian Alliance and PCs won in 2000.

If something similar happens to the UCP, the 52 per cent the Alberta PCs and Wildrose combined for in 2015 would be reduced to about 41 per cent — matching the Alberta NDP's vote share in that election.

An 'accidental' NDP government?

The New Democrats' historic breakthrough in 2015 has been dismissed as "accidental" by PC Leader Jason Kenney. The premise of the UCP merger is that, had the two parties not been split in 2015, the New Democrats would never have come to power.

While it is true that the combined 52 per cent support for the PCs and Wildrose would have been enough to win a majority government had it not been split between the two parties, those voters would not have united behind one party had they been forced to make that choice.

A late campaign poll by Ipsos found that 33 per cent of Wildrose voters and 19 per cent of PC voters ranked the NDP as their second choice. Just a third or less listed the other conservative option as their second choice.

Polls suggest that Albertans did not expect the New Democrats to win in 2015, but they also indicate that a majority of voters were more interested in defeating the PC government than preventing the New Democrats from taking office — undermining the contention that a divided right elected the NDP.

On track for defeat

But public opinion has shifted since then. The New Democrats are now polling in the mid-20s in support and Notley's approval is around 30 per cent, half of what it was when she was first elected.

Whether or not the right is divided, the NDP is on track for defeat with those numbers.

With a little less than two years to go before the next scheduled election, however, the NDP has time to put itself back into contention. If the PCs and Wildrose had not voted to merge, the NDP could have been re-elected in a scenario that split the vote three ways between the PCs, Wildrose and New Democrats.

In such a scenario, the NDP would likely have retained most, if not all, of its seats in Edmonton and stood a decent chance of benefiting from PC/Wildrose splits to win enough seats in Calgary and the rest of the province to hold on to power. This was likely the potential outcome that kept Kenney and Wildrose Leader Brian Jean up at night.

Wildrose Leader Brian Jean celebrates the 'yes' vote at the Wildrose special general meeting in Red Deer on Saturday. (Jason Franson/The Canadian Press )

But with the advent of the UCP, the New Democrats will be in a tough spot without a significant increase in their government's popularity. Even if the UCP loses as much support as the federal Conservatives did in their first election as a united party — perhaps leaking votes to centrist options like the Liberals or Alberta Party — the NDP would need to retain all of its 2015 support to stand a chance. The party isn't on the path to meeting that target.

Nevertheless, the UCP would be wise to not take their unity for granted. A merged party can turn out to be less than the sum of its parts.