One quibble with the mode of analysis for taxation. The way to evaluate the impact, positive or negative, of government spending, would be the effect of the spending vs the average counterfactual effect of retention. Thus, for impact analysis, we would not be comparing the utility generated from government spending to the cost-effectiveness of a marginal dollar to a Givewell-endorse charity, but rather the utility generated by the counterfactual retention of the funds by the taxpayer base. In any case, that bar is much easier for government spending to clear.
One quibble with the mode of analysis for taxation. The way to evaluate the impact, positive or negative, of government spending, would be the effect of the spending vs the average counterfactual effect of retention. Thus, for impact analysis, we would not be comparing the utility generated from government spending to the cost-effectiveness of a marginal dollar to a Givewell-endorse charity, but rather the utility generated by the counterfactual retention of the funds by the taxpayer base. In any case, that bar is much easier for government spending to clear.