OTTAWA — The Prime Minister's Office has warned Conservative MPs not to comment on the marriage next month of two gay RCMP constables.

The gag order went to all MPs but was aimed at "the small minority who might say something stupid,'' said one caucus member.

It's just the latest in a concerted effort by Prime Minister Stephen Harper to control and limit his new government's public message track.

And it follows party strategists' successful suppression during the election campaign of outspoken social conservatives whose opinions might have harmed the party's climb to power.

At one of Harper's campaign events in January, party officials spirited a well-known anti-abortion advocate into a back kitchen -- in full view of bemused reporters -- rather than risk the local Tory candidate's views being aired by the media.

Now the marriage of RCMP constables Jason Tree and David Connors in Yarmouth, N.S., appears to be causing some unease in the PMO.

Sandra Buckler, Harper's director of communications, was not available for comment Thursday. But several Conservative MPs quietly confirmed they had received the PMO gag order after the story of the Mountie wedding received widespread media coverage last week.

Opposition MPs said the gag order is telling.

"It shows that Stephen Harper does not trust his own caucus to avoid social Neanderthalism on these issues,'' said Liberal MP Scott Brison.

"And if he doesn't trust his caucus to be socially progressive, then why should Canadians trust his party to be socially progressive?''

NDP MP Libby Davies said the PMO note should have carried a very different directive: "What I would hope the (party) message would be is to congratulate these two officers who are obviously in love and want to get married.''

Conservatives will likely insist this is simply a matter of sticking to the government's core priorities.

"It's always the role of a government to communicate its own message,'' Harper said Thursday in Vancouver, responding in French to a question about his picayune standoff with the parliamentary press gallery over who gets to decide who asks questions at news conferences.

"It is the government that has the right to communicate with the population.''

Make no mistake, the government in this case means Harper and his strategists in the Langevin Block across the street from the Parliament Hill.

Ian Brodie, Harper's chief of staff, has warned cabinet ministers that if they stray off message they face an escalating scale of sanctions, ranging from public humiliation to removal from cabinet. Foreign Affairs Minister Peter MacKay and Industry Minister Maxime Bernier have already felt the sting.

But Harper's preoccupation with message control extends far beyond his front bench.

Maverick Conservative MP Garth Turner went public early in February with accounts of being sternly dressed down by the prime minister for speaking out on David Emerson's defection from the Liberals.

Saskatchewan MP Garry Breitkreuz, a party stalwart and longtime leading advocate of scrapping the federal long-gun registry, was ordered not to talk with reporters about federal gun legislation in advance of last week's amnesty announcement by Public Security Minister Stockwell Day.

General Rick Hillier, the Chief of Defence Staff, went so far as to publicly deny published reports last month that he'd been muzzled -- although the blunt-spoken Newfoundlander has avoided public comment ever since.

On Wednesday night in Calgary, Justice Minister Vic Toews insisted all questions be screened in advance during a town hall discussion on the government's get-tough-on-crime bill.