[ZeroGravitas]

If they argued for some counterbalancing arrangement with the money raised they were probably on the left if they just said "well, I guess we just have to stick with what we currently do, it's not like government intervention would be desirable here" then they were probably not actually on the left.

[DuskStar]

The initial proposal was for the carbon tax to be revenue-neutral and (IIRC) returned as a per-capita rebate. That didn't pass, so the followup used the revenue for social programs as an attempt at bipartisanship. The followup also failed to pass, though.