Here we go again.

It seems as if we can't have a federal election in Canada without arguing about the corporate tax rate.

Surely you remember the 2008 campaign when the NDP proposed raising the rate to 22.12 per cent.

Or how about 2011, when the Liberals called for a halt to a series of Conservative corporate tax cuts, and to restore the rate from 16.5 to 18 per cent.

Meanwhile, the NDP was a bit vague on its numbers that election, but vowed to "keep Canada's corporate tax rate competitive by ensuring that our combined federal/provincial corporate income tax rate is always below the United States federal corporate tax rate."

That would have been an easy promise to keep, since the difference between Canada and the U.S. in 2011 was nine percentage points in combined federal and provincial/state corporate taxes. The NDP could have raised Canada's corporate rate to heights not seen in decades, and still have kept that promise.

And now, four years later, the Conservatives and Liberals want to leave the rate at its current 15 per cent, while the NDP wants to raise it to 17 per cent. The party forecasts that hike will bring in $3.7 billion a year in extra revenue.

It also wants to cut the tax rate for small businesses from 11 per cent to nine per cent by 2017. In its budget last spring, the Conservative government proposed making the same cut by 2019, a plan supported by the Liberals.

The spin

The NDP argues that even with the two per cent increase it is proposing, Canada's corporate tax rate would still be well below that of our biggest trading partner, the U.S., and well below most other G7 and G20 countries.

And that's right. The combined corporate tax rate — including provincial levies — is 26.3 per cent, second- lowest among the industrialized G7 nations, according to data from the Organization for Economic Co-operation and Development.

The U.S. federal rate is a lofty 35 per cent and has been since 1993. Combine that with state taxes, and the American rate is close to 40 per cent, almost 13 percentage points higher than in Canada.

So it's hard to imagine businesses fleeing across the border to escape a two percentage point tax hike.

The counter-spin

Under the Conservatives, the corporate tax rate has fallen from 21 per cent when they took office in 2006, to 15 per cent today. Not surprisingly, they are not happy about that downward trajectory being reversed.

Candidates Michelle Rempel, Andrew Thomson and John McCallum discuss the NDP's fiscal plan 16:33

They tweeted that the NDP tax hikes would cost 250,000 jobs across Canada. They also argue that corporations will simply shift money around to avoid paying a higher Canadian rate.

The Liberals were a bit more conservative on the job number. Former finance minister John McCallum told reporters that the NDP platform would cost 200,000 jobs.

He also claimed the NDP had seriously over-estimated the amount of revenue that the tax hike would generate.

The rinse

The job loss numbers are a bit of a mug's game.

All kinds of factors go in to a company's decision to increase or decrease its workforce. Tax rates are only one of them.

Given all that's intervened, it is hard to argue that the steep decline in Canada's corporate tax rate since 2006 has led to a substantial increase in hiring, but who knows? The job numbers may have been even worse if the tax rate had remained over 20 per cent.

Some tax experts, like Calgary-based economist Jack Mintz, argue that raising the corporate tax rate is unfair and "mildly regressive" in that it often forces corporations to shift the burden onto employees, in the form of lower wages or job cuts, or consumers, in the form of higher prices.

The Liberals may have a point about the revenue projections. The NDP bases its $3.7 billion in extra revenue on figures from last April's Conservative budget.

But the economy has weakened since then, and future growth (meaning taxable corporate profits) is now projected to be considerably lower this year and next.

The NDP might also be putting too much weight on comparing Canadian tax rates with the U.S. and other G7 countries. What you see is not necessarily what they pay.

If you think that giant American-based corporations like Apple, Google or General Electric actually pay 40 per cent in corporate taxes, then you clearly don't understand international finance.

Those companies stash vast hoards of money in countries with much lower tax rates than Canada could ever hope to achieve, like Ireland, where the combined tax rate is just 12.5 per cent. It is estimated that Google pays as little as 2.4 per cent tax on its billions of offshore profits.

Conservative Leader Stephen Harper checks out an acoustic guitar with Mike Miltimore, owner of Riversong, a guitar company in Kamloops, B.C. All parties favour lowering the small business tax rate. It's not clear, though, if this will contribute to more jobs. (Ryan Remiorz/Canadian Press)

So even with an increase to 17 per cent in the federal rate, Canada should remain competitive when compared to its largest trading partners. But if large Canadian-based corporations want to avoid paying that increase, they probably can and will.

Mid-sized companies don't always have that luxury and have often touted Canada's low corporate tax rate as an incentive for investment here. If the federal rate is to rise, these groups will undoubtedly bring pressure on cash-strapped provincial governments to lower their portions, to keep them competitive.

As for the proposed cut to small business taxes (to nine from 11 per cent), that is being hailed by the NDP as a boost to the "real" job creators.

The party claims small businesses employ nearly eight million Canadians, and the tax cut will encourage them to hire even more.

The problem is that most of those jobs are not the high-paid, unionized, secure jobs that the NDP is hoping will replace the precarious employment that millions of Canadians are now experiencing.

Those good jobs are more likely to be found in big companies, not small ones, which raises the question of who should really be getting the tax cut?