Politicians lacking vision (like Mr. Prentice) launch trial balloons left, right and centre in the hope that somewhere along the line they'll get it right. This demonstrates a lack of conviction in the party's platform or a lack of confidence in the government's ability to explain difficult issues to the electorate.
Earn $17,787 in Alberta and you'll pay nothing in provincial income tax. Earn $50,000 and 6.4 per cent of your income is tax ($50,000 minus the $17,787 exemption; the 10 per cent tax is paid on the remaining $32,213). Earn $100,000 and 8.2 per cent of your income is tax. There's a word for such sliding proportions of tax paid: progressive.