Politically, I doubt the Cons will move any votes from Lib or NDP supporters. People who didn't already support the Cons aren't going to come running in gushing, "My heroes!" just for this. I suppose a few really pissed-off Con supporters will move to non-traditional candidates or just not vote as a protest. If the Cons felt they had to do it, then politically it was better to do it as early as possible before the next election. It was also necessary to do it now if they specifically wanted to put the brakes on the BCE and Telus conversions (some of the rumours in the media are interesting).
Fiscally, the foregone federal revenue (existing trusts) has been smaller (in some years, much smaller) than annual federal surpluses. The alleged "loss" from the BCE and Telus proposed conversions ignores the fact that neither company has had a net federal payable for the past few years (no idea exactly how many) and that companies can pursue other strategies to pay no tax (eg. a purchase of MTS by either Telus or BCE in order to grab MTS's tax losses is one speculation in media). To count BCE and Telus federal corporate tax revenues is to count a chicken which has not yet hatched. Many people forget that there isn't really any such thing as "corporate" tax - in the end, it's tax paid by shareholders, owners, and employees. Corporate income tax is just indirect personal income tax. From the numbers I've looked at, to have your corporate investments subjected to corporate tax rates and then dividend tax rates is in general favourable to paying straight personal tax rates (22% and 26% regimes) as income. It might not apply for people with stratospheric incomes, but all the sound and fury about corporations paying their "fair share" really supports having investors pay "less than their fair share". I do love irony. Also from the investor's perspective, conversions can result in an immediate capital gains assessment (but that can sometimes be deferred); however, ultimately if you've bought shares or units you will pay capital gains sometime unless you hold them until you die. In the specific cases (Telus, BCE), shareholders complaining about paying the gains have a peculiarly glass-half-empty view: your shares jumped in value and your payouts will most likely be higher year-after-year, but you might have to pay some gains now rather than later. It reminds me of Guard Hadley's attitude toward his windfall in "Shawshank Redemption".
Where there is genuine leakage is to foreign investors. There are deferred taxes for trusts held by pension funds and RRSP accounts; corporate taxes take a chunk out of non-trust investments. (One may argue that in the spirit of fairness, a sheltered investment should be a sheltered investment, period.) And, there are the issues of the true net effects with respect to each province.
With respect to losses, no-one lost anything unless they actually dumped shares/units for less than they paid. The book value of the share valuation write-down isn't really a first-rank indicator of anything except an illustration that to really destroy wealth, you should first become government. I hold shares - when the value goes up I haven't gained anything unless I sell; when it falls, I haven't lost anything unless I sell. People who truly got caught may be those who bought Telus and/or BCE during the share valuation climb-up in the expectation of receiving higher payouts after the trust conversions. The companies made good-faith, considered decisions with respect to the government's stated position, and investors made good-faith, considered decisions with respect to the government and the companies' positions. I guess they get to pay for the governments flip-flop: "my mistake, your fault".
The moral issue of tax avoidance has been mentioned in several quarters in the media. On them, I call bullsh!t. Paying attention to the regulatory structure is as important as paying attention to the behaviour of the markets and any other relevant factors. Working a tax advantage is no less seemly than working any other advantage for which one person might qualify but not another due to arbitrary and perhaps unattainable criteria.
The other stupidity - not meaning to single you out, Arthur - that was widely raised is the idea that passing profits through to investors is bad for the economy and anti-capitalistic and hobbles productivity gains. Everyone who made that claim forgot the meaning of the word "investor". What's bad for productivity gains are weak executive decisions and too much capital in the hands of businesses which can't find uses for capital quickly enough. The entire community of investors, from advisors and fund managers to individuals, constantly monitors opportunities. Who better to make decisions about the allocation of capital? A badly run company doesn't favour the economy by hanging onto its profits (if it has any).