Room for progressivity

Yes, I know some commentators are treating the latest from Kevin Milligan et al. as somehow proving a point that raising high-income tax levels won't accomplish anything. But I'd think one has to strain rather hard to draw such an interpretation from a column that includes the following:

What might an increase in taxes for the highest earners look like? Brian Topp, one of the front-running federal NDP leadership hopefuls, has recently proposed a new 35-per-cent federal tax bracket for those with incomes over $250,000. A new tax bracket like this wouldn't actually hit very many of us. Fewer than one per cent of us earn more than $250,000, and the tax on dollars earned under that threshold would not change. So, more than 99 per cent would see no change under this proposal. The combined federal-provincial top rate in B.C. would be 49.7 per cent instead of 43.7 per cent. This isn't out of line with other jurisdictions: the top rate in the U.K. is 50 per cent and the proposed top rate for 2012 in California is 46.3 per cent. For those with longer memories, the top rate in Canada 40 years ago in 1971 was 80 per cent.
...
Brian Topp assumes his proposed 35-per-cent federal rate would yield $3 billion in new revenues. Economists have fairly good estimates of how much revenue "slippage" we might expect for top earners, and these estimates suggest the additional revenue might slip down closer to $1.5 billion. These same estimates suggest that if we pushed the combined top tax rate too close to 60 per cent, higher taxes would stop yielding much new revenue at all.

So Milligan et al. see room to increase our current high-earner tax rates by upwards of 15 per cent of income before we'd approach the optimal level of public revenue. And that revenue would include not only the added $1.5 billion per year anticipated as part of Topp's plan, but the inflow from increasing the current rates substantially more (albeit with diminishing returns along the way).

So there looks to be ample room to increase taxes on those who can afford it most - and substantial returns to be generated in the process. And we should be eager to highlight those opportunities as the Cons try to tell Canadians that we can't afford anything but an era for austerity for everybody but the corporate sector.