In August 2005, six months before Paul Martin actually got around to stepping aside, Maclean's magazine reported that Frank McKenna was the front-runner to be the next Liberal leader. Also mentioned were Michael Ignatieff, Bob Rae, Ken Dryden and John Manley.

At least three of those people — Ignatieff, Rae and Dryden — actually ended up running for the party leadership in 2006. And one of them — Ignatieff — eventually became Liberal leader, though not until 2008, at which point he proceeded to lead the party to the worst result in its history.

McKenna officially renounced any interest in January 2006, shortly after Martin actually resigned.

Two and a half years later, after Sté​phane Dion had tried and failed, McKenna was compelled to publicly pass for a second time.

And four years after that, in the wake of Ignatieff's fall, McKenna's not running was news for a third time.

Next to actually being prime minister, here is the greatest honour a country can bestow on one of its sons or daughters: to be touted as a possible leadership contender. It is at least a vastly superior fate to actually leading a political party and failing at the task.

And it is this that Peter MacKay, and his fellow abstainers in the sitting-this-one-out class of 2016, might aspire to. In lieu of actually running, aim for enduring plausibility.

Frank McKenna, who declined to run for Liberal leader in 2006, 2008 and 2012. (Chris Young/CP)

The abstaining class of 2016

At present, with two open races for federal party leaderships, the tally of officially declined is longer than the list of actual contestants, the former including MacKay, Jason Kenney, James Moore and Brad Wall for the Conservatives alongside Megan Leslie, Nathan Cullen and Alexandre Boulerice for the New Democrats.

And still, other possibilities abound.

Kevin O'Leary, the television personality, has spent the last nine months talking about how he might decide to try to lead the Conservatives and is now said to be "licking [his] chops" at the prospect even while he says he might still pass. And there was a brief spasm of excitement this week when Doug Ford, brother of Rob and a former city councillor in Toronto, announced he had something exciting to announce.

Alas, it turned out he just has a book to promote.

If both Ford and O'Leary take a pass they will join a burgeoning pantheon of the publicly considered, but ultimately demurring.

Bernard Lord didn't run for the Conservatives in 2004, nor in 2015. (Nathan Denette/Canadian Press)

The demurring hall of fame

Going back to the first race to lead a united Conservative party in 2004, there were the speculated candidacies of former Ontario premier Mike Harris and Bernard Lord, former premier of New Brunswick that never came to fruition. In 2006, McKenna was joined in publicly passing by former cabinet ministers John Manley, Brian Tobin and Allan Rock. And it was necessary for Manley to decline again in 2008.

Gary Doer and Olivia Chow were unsuccessfully touted as possible candidates for the NDP leadership in 2011. Bernard Lord and Jean Charest were compelled to disavow any interest in the Conservative leadership last fall. And Avi Lewis has had to renounce any interest in leading the federal NDP.

Some concession to reality is probably in order.

Politicians, despite outward appearances, are human beings, with concerns about their families and personal happiness. Leading a major federal party does not seem like fun. Being leader of the opposition is a particularly awful task. Possibly, you could find a more lucrative job with better hours.

"This is a hugely personal decision, as well as political," says Manley. "And there is a broad assumption that people are in politics always with an eye to how they can rise to the top. For some, I'm sure that's true. But it totally understates the extent of the sacrifices involved."

Anyone now seeking to lead the Conservatives or New Democrats has to consider the possibility of a 16-year commitment: eight years in opposition and another eight as prime minister.

And actually running carries the distinct risk of miserable failure.

The enduring allure of never having run

The hypothetical candidate still holds some potential. The unsuccessful leader is a confirmed disappointment. In an alternate reality, Michael Ignatieff or Jim Prentice, for instance, are still merely the former.

"Reputationally and perhaps commercially, it's better to be thought of as the best prime minister we never had than one of the worst candidates to ever present themselves," Manley says. "Nobody can ever test whether I would have been a good prime minister."

Possibly that is still a risk worth taking. But unsullied are those who are logged in the Wikipedia entry under the heading of "declined to run."

We, the political class, might reflect on the last 13 years and wonder how much time we have wasted wondering about things that never came to pass, all in addition to the time we have unquestionably wasted on speculating about who might be moved in the next cabinet shuffle.

But then what fun would remain if we stopped entertaining the myriad possibilities contained in the unknown political future?

MacKay's exit from current consideration was detailed in a 680-word statement, five of which were "at this time" and "right now." And therein is an invitation.

Declining in 2016 happily creates a basis for speculating in 2019, and then perhaps again in 2023. A run at McKenna's unofficial record is not out of the question.