The English angle shows up in these sentences:
"That is that both the federal and Ontario governments are implementing a series of corporate tax cuts that deplete public revenues by billions of dollars every year."
"Stephen Harper’s corporate tax cuts will end up depleting federal revenues by nearly $14 billion every year."I'm not aware of having seen deplete used this way before, and after searching a wide range of style books (including MWDEU), I find none have noted this creative use of deplete or depletion. You can deplete ozone, resources, water reserves, energy supplies, substances, stocks, nutrients, savings, soil, populations, and funds, but all of these have in common that they are entities or quantities; they are (or can be) replete. Revenue, on the other hand, is simply a measure of change (it shows up on the income statement, not the balance sheet). People don't typically speak of depleting velocity, for instance or depleting aging.
But Cartwright's use here is, I think, calculated to make us feel a loss. It's spin, pure and simple. I wonder if you can deplete spin.