In a week blissfully free of fresh terrorist atrocities, it now appears that the security wave which propelled Stephen Harper into a clear lead has run out of momentum.

The Conservatives have declined three points and the Liberals have risen slightly, by an insignificant two points. The demographic and regional shifts support the theory that terrorism’s lower political salience in the absence of recent attacks is driving this modest, but statistically significant, shift.

Support from the less well-educated and male voters has dropped more steeply for Stephen Harper, as has his net approval score. It’s possible the government’s recent florid hyperbole on the jihadist threat has actually overshot voters’ capacity for suspending disbelief. The regional patterns are also relatively stable, with a slight shift in favour of the Liberals in the critical Ontario and Quebec arenas.

The other significant shift in an otherwise quiet polling period was a nine-point improvement in Justin Trudeau’s net approval score. This may be significant, as his approval score has been stuck or slightly declining for some time. The net shift in the relative positioning of Trudeau versus Harper is a significant disruption of what had been a quite favourable trend in Harper’s favour.

Tom Mulcair’s score is also improving somewhat. The opposition leaders have had trouble gaining much attention or traction against the recent fixation on security and terror; that may be changing now.

The argument that Stephen Harper is losing some of his security-driven support is reinforced by the fact that we see no corresponding decline in broad directional approval — which is actually up slightly.

Some of the other diagnostic tracking suggests that the more salient issue — the economy — is reasserting itself and that this is terrain much less favourable for the Conservatives than the terror file.

The economy (jobs and growth) is the dominant issue by an increasing margin in one of our key issue tracking tests, opening up a 12-point lead on social issues (which were tied not that long ago). The economy now ranks as the dominant issue in all regions of the country and across all demographics — with the exception of youth, who lean more towards social issues. Social issues come up more often in Quebec, among women, and among university graduates, while fiscal issues are becoming an important issue in Alberta.

Another, newer forced-choice test that arrays security, the environment and democratic renewal shows that “restoring the middle class” outstrips all of those other important issues by a margin of well over two to one. The salience of the middle class issue transcends partisan lines and we believe it may well be the critical ballot question in October (or sooner). The issue is particularly strong with francophones, the labour vote, boomers and Generation X. These are all critical constituencies for the Liberals and, in particular, the NDP, who continue to falter well below their levels of the last election.

There isn’t much cheer out there about the way the economy has been working and the patterns suggest progress is halting — possibly even reversing.

Canadians’ economic confidence is extremely low these days and gets worse as we move further into an increasingly cloudy future. Canadians’ sense of progress versus decline is clearly tilting away from a fairly evenly divided set of views to one where people are now leaning more towards a sense of stagnation and decline. Less than one in five reports having improved their positions over the past year or the past five-year period.

It’s intriguing to see how political party allegiance and economic progress intersect. While no party supporters actually report having moved forward much, the incidence of progress is much higher among those who support the Conservatives. So while the economy hasn’t worked very well, it has worked much better for Canadians who support the government — but even there, the sense of progress over the past year is down sharply.

All of which suggests the economy, and the goal of restoring middle class progress, will almost certainly eclipse the security issue when voters vote.

While we make no comment on the merit of Eve Adams’ decision to cross the floor to the Liberal party, it is our experience that the public tends to be less troubled by questions of caucus loyalty than insiders and party faithful. We do not believe that this incident will be a factor in the outcome of the next election — but it can be linked to broader trends.

The Canadian public seems to be moving away from the politics of polarization. In 2011, we started seeing a trend of Canadians abandoning the political centre and moving to either the left or the right, as evidenced by the success of the Conservatives and NDP and the near-demise of the Liberal party. Indeed, it appeared that Canadians were moving towards a U.S.-style climate of political polarization, where voters are divided between two irreconcilable ‘armed’ camps. However, it now appears that the centre-left may now be moving away from that path. At the very least, non-Conservative voters are not currently being drawn to an alternative left-option — a political yin to Stephen Harper’s yang. For the time being, they are increasingly opting for a centrist option.

We asked Canadians who they voted for in the 2011 election and compared their responses to who they intend to vote for in the upcoming election. The results show that only about half of current Liberal supporters voted Liberal four years ago (hardly surprising considering they captured less than one-fifth of the vote). What is interesting, however, is that the Liberals have drawn their new support equally from both Conservative and the NDP camps (as well as returning and new voters). In other words, there are as many former Conservatives in the party as there are former NDP supporters.

All of this suggests that Mr. Trudeau is at least temporarily re-establishing his party as a centrist party and is re-constructing the constituencies that were key to the party’s success in the 1990s.

Frank Graves is founder and president of EKOS Polling.