How much longer can the Liberal-NDP deal last?

On Thursday, Conservative Leader Pierre Poilievre made a great show — he even wrote a letter — of calling on NDP Leader Jagmeet Singh to walk away from the NDP's supply-and-confidence agreement with the Liberal government.

Poilievre alleged that Singh was sticking with the deal so that he could become eligible for a parliamentary pension (Poilievre qualified for an MP pension in 2010, when he was 31 years old).

For that reason, Poilievre said, «Canadians are now calling him 'Sellout Singh'» — the nickname Poilievre himself has given the NDP leader. (Poilievre's fondness for nicknames recalls a certain American presidential candidate.)

It's perhaps not a coincidence that Poilievre's call came in the midst of a byelection campaign in Elmwood–Transcona, a Manitoba riding where Conservatives have traditionally finished second to the NDP.

For that matter, Poilievre's broader interest in Singh no doubt has something to do with the fact that some of the Conservative Party's best hopes for gains in the next election are ridings in British Columbia and northern Ontario that are currently represented by NDP MPs.

Poilievre had barely finished speaking before the Conservative Party sent out a fundraising appeal, informing supporters that the Conservative leader had just «challenged» Singh «to PULL OUT of the carbon tax coalition.»

In response, the NDP more or less shrugged, though they did allow that they could always walk away from the deal.

Formal agreement first of its kind

The historic supply-and-confidence agreement between the Liberals and NDP — the first such formal deal between two parties at the federal level, though there were provincial precedents — is now two and a half years old. And with that agreement underpinning the