The basic principle was simple — support conservative candidates, but do it quietly.
So much for that.
Tory MPs have involved themselves deeply and publicly in both the provincial election in Alberta and the Progressive Conservative leadership contest in Ontario.
In the latter race, many Conservatives are directly flouting the 2011 edict, which prohibited ministers from endorsing candidates and suggested MPs ought to remain neutral and do no general campaigning.
A spokesman for the prime minister's office wouldn't say why the rules appear to have changed.
"Members of Parliament are free to support and endorse the provincial party of their choosing," Stephen Lecce said in an email.
The shift seemed to begin during the 2014 Ontario provincial election when senior Tory ministers and staffers took public swipes at Ontario Liberal leader Kathleen Wynne.
Strategists say it is a reflection of the Conservatives seeking to keep their base engaged and to keep those voters from looking for somewhere else to park their support come the fall election.
"The rise of Justin Trudeau also means the rise of vote splitting and so everybody is quite united against that," said Michele Austin, a senior adviser with Summa Strategies.
"I think the Conservatives have realized it and are allowing people to speak their mind."
Alberta Tories were divided in the last provincial election, because two conservative parties were vying for voters. Most federal MPs backed the more right-wing Wildrose Alliance.
This time around, federal Tories have united in a bid to stop the surge in NDP support in the province. Many are circulating news releases, posting on Twitter and giving interviews about the supposed risk of electing the NDP, rather than discussing which conservative candidate to endorse.
Ahead of the Alberta vote Tuesday, some said they saw no problem with such intense partisan engagement in the campaign.
"It's part and parcel of being an Albertan," said Calgary MP Deepak Obhrai.
Others, speaking only on background, said they were deliberately staying a bit more behind the scenes, in part because they'll have to work with whomever is elected.
There's also the risk of alienating voters in their own ridings, something seemingly born out in a Facebook post by MP Chris Warkentin.
He posted comments he made in the House of Commons last week decrying provincial NDP policies and many people wrote back, saying they felt it wasn't his place to tell them how to vote.
The post appears to have since been deleted.
In the Ontario Progressive Conservative leadership race, which wraps up this weekend, one contender is a Conservative MP, Patrick Brown, while another is Christine Elliott, who has close ties to the federal Tories in part because her late husband was Jim Flaherty, Harper's former finance minister.
Many federal MPs are expected at Saturday's vote and have been out on the hustings with the candidates, though there's been little evidence of caucus tension over who supports whom.
Conservative cabinet minister Pierre Poilievre, who supports Brown, said he thinks it's his right to pick a horse to back.
"I'm a taxpayer here in Ontario, it's fair for me to get involved," he said.
Also on HuffPost