It is to the extent that it is evidence of the very bias she is trying to prove.
Did you bother to look up what the income level for that high tax rate under Truman was? It was US$400K. That translates to somewhere in the range of US$3-4M today (depending on the calculator you use), which would convert to CAD$4-5M. Only a very tiny fraction of the population in this country makes that much money (in 2014, less than 1% of Canadians made over $200,000, let alone $5M) or even has that much in assets (< 0.1% per the Financial Post article below) so you're actually not going to get much revenue out of it. Thus, there is no argument for it other than it being a punishment for wealth.
http://federal-tax-rates.insidegov.com/d/a/Harry-S.-Truman
http://www.statcan.gc.ca/tables-tableaux/sum-som/l01/cst01/famil105a-eng.htm
http://business.financialpost.com/p...ich-heres-how-to-tell-and-why-you-should-care
How do the wealthy get wealthy? IME, many of them work for it. They develop a product or service and are successful in selling it. Why punish that?
Example:
Two UW grads just sold their AI startup to MS. I haven't heard figures (it was privately held so nothing has to be filed publicly until MS reports to shareholders) but I'll bet they are now multimillionaires given MS's history of generous takeover offers. Are you going to punish them for their success by making them give 90% of that to the government, esp. given that history shows that they will most likely take that money and use it to start another company with another product (tech entrepreneurs have a history of jumping from startup to startup)? These people are creating jobs, and creating technologies that help others create jobs. Why do you want to punish that success? Are we expecting people like this to donate their hard work to society?
All you'd accomplish with your tax proposal is to send anyone with that kind of talent to a country with less punitive taxes. As it is, we lose a lot of our best and brightest to Silicon Valley (did you know that Uber was co-founded by a Canuck who now chairs their board and is worth an estimated US$5.3 billion?). You'd just turn that into a wholesale exodus. Punishing wealth willy-nilly breeds mediocrity because it also punishes success.
Yes, take down some of the tax shelters and dicey deductions.
Yes, bring in a minimum tax level
Yes, go after off-shoring
But punitive taxes like you propose will only make the rich more willing to use dodges or simply pack up and leave.