Details of President Donald Trump’s first budget have now been released. Much can and will be said about the dire social consequences about what is in it and the wildly optimistic economic assumptions it embodies. My observation is that there appears to be a logical error of the kind that would justify failing a student in an introductory economics course.

Apparently, the budget forecasts that US growth will rise to 3.0 per cent by 2021 because of the Trump administration’s policies — largely its tax cuts and perhaps also its regulatory policies. Fair enough if you believe in tooth-fairies and ludicrous supply-side economics.

Then the administration asserts that it will propose revenue-neutral tax cuts, with the revenue neutrality coming in part because the tax cuts stimulate growth! This is an elementary double count. You cannot use the growth benefits of tax cuts once to justify an optimistic baseline and then again to claim that the tax cuts do not cost revenue. At least not in a world of logic.