Everybody knows that federal public servants—from senior mandarins to lowly government minions—get better pensions than most private-sector workers. But now the C.D. Howe institute says the $140 billion the government budgeted last year for paying out those pensions in the future isn’t nearly enough. Instead, the private think-tank argues the liability should be $198 billion. It’s an arcane argument over how the cost of financing pensions is calculated. But the debate has real impact on the national debt.