Lt. General (ret’d) Andrew Leslie speaks to delegates on day two of the Liberal Party of Canada's biennial convention in Montreal, Friday, February 21, 2014. THE CANADIAN PRESS/Graham Hughes

OTTAWA — Federal Conservatives are putting a new twist on an old tactic: spying on political opponents.

They’re no longer content to send observers to rival parties’ public events, passively monitoring proceedings in hopes of spotting a gaffe that can be exploited. They’re now employing agents provocateur who actively try to instigate a miscue, secretly record it and then leak it to the media.

Liberals, who’ve been on the receiving end of the ploy twice in the past three months, call the tactic entrapment, unethical and “Nixonian.” And they worry it could lead to the end of candour in federal politics, with wary politicians reduced to mouthing platitudes and reciting carefully scripted talking points.

But the Conservatives are making no apologies. They maintain Canadians have a right to know what Liberal MPs and candidates really think, particularly if their candid views are at odds with those of their leader, Justin Trudeau.

“It’s not surprising that Liberals don’t want Canadians to know what their true feelings are on important issues,” Conservative party spokesman Cory Hann told The Canadian Press.

“What the Liberals are really upset about is that they were caught having one of Trudeau’s top advisers deliver anti-Israel messages to certain segments of the Canadian public … (And) I can see why the Liberals don’t want it known that a senior Liberal MP thinks Justin Trudeau is a bozo and in over his head.”

Hann was referring to retired general Andrew Leslie, a star Liberal recruit who advises Trudeau on foreign policy, and veteran Toronto MP John McKay, both of whom have fallen victim to the Tory sting operation.

Earlier this week, Sun News Network received a recording from a roundtable discussion Leslie hosted last month on veterans’ issues, during which a young woman — identified by the Liberals as Alexandra Constantinidis, parliamentary assistant to Conservative MP Rob Anders — asked the would-be Liberal candidate about his views on the Israel-Hamas conflict in Gaza.

In the course of a lengthy response in which he asserted Israel’s right to defend itself and to kill members of terrorist organizations such as Hamas, Leslie criticized Israel for “firing indiscriminately” on Palestinian women and children.

According to the Liberals, the Conservatives first offered the recording to the Centre for Israel and Jewish Affairs, which refused to get involved. The CIJA declined to confirm or deny that assertion but issued a careful statement from CEO Shimon Fogel to The Canadian Press.

“We have met with General Leslie previously. We know the General to be fully appreciative of the security challenges facing Israelis and shares our view as to Israel’s responsibility to defend itself and the destructive influence of Hamas,” Fogel said.

“His choice of words regarding Israel’s tactics was unfortunate and we look forward to meeting with him again to receive reassurances that his views are consistent with those articulated by Justin Trudeau.”

The Conservatives have not been so guarded. The party sent out a fundraising email blast mid-week, slamming Leslie’s “stunning lack of awareness of the dangers Israel faces,” asserting that his comments reveal “the Liberals’ true position on Israel” and proclaiming that “only the Conservatives’ stand on Israel is reasonable and right.”