Prime Minister Stephen Harper is hinting that Ottawa means to scale back Old Age Security payments. At the recent meeting of the World Economic Forum in Switzerland, the prime minister promised sweeping changes in Canada's retirement programs.

Pushed for details, Harper promised he won't cut benefit levels under the Old Age Security plan - but he left open a possibility that the entry level might be pushed back, from age 65 to 67.

In one respect, the prime minister is right to be concerned. OAS costs $36 billion. But due to the rapid aging of Canada's population, the bill will triple to $108 billion by 2030.

That's a problem, because OAS is paid out of general revenues. Unlike the Canada Pension Plan, it is not funded by workers' contributions.

Taxpayers are on the hook for the whole amount. Clearly there are challenges ahead.

But let's stop right here, and get some facts straight. OAS is Canada's most basic safety net program.

The allowance tops out at $540 per month - hardly a generous amount. Moreover, the program is income tested. The full payment is only available for retirees who earn less than $68,000 per year.

More importantly, OAS is part of our social contract. It was introduced in 1951 with a rare constitutional amendment, making it as close to a solemn promise as any legislative scheme gets.

While a two-year deferral of payments may not sound dramatic, it would cost the neediest Canadians $12,960. Is that really what the prime minister has in mind?

If so, two pieces of context may help him reconsider. First, the cost increase noted above is really quite modest when looked at more broadly.

At this time, OAS payments equal 2.3 per cent of the national economy. In 2030, the top of the cost pyramid, they will nudge up to 3.1 per cent.

In itself, that's hardly a staggering blow. And after the peak is reached, costs will decline again. The correct solution is to build a reserve now so that future bills can be met without cutting benefits.

Second, the annual ceiling under OAS is $6,480, and that's only available at age 65.

By comparison, our MPs are eligible for a minimum pension of $40,000, which they can collect at 55, after only six years in Parliament.

Moreover, while most work-based pensions are equally funded by the employer and the employee, taxpayers finance virtually all of the MPs' pension scheme. For every $1 our elected representatives contribute, we cough up $23.

So if there are going to be pension reforms, let's focus instead on Parliament's outrageous scheme. And here's a suggestion for how to proceed.

If parliamentarians want a pension after just six years of work, let's use the same formula that applies in the real world.

By our math, they would receive around $6,480 - just what an OAS recipient gets.

That sounds about right.