When the deficit's "under control", will the Conservatives be able to resist deficit-funded tax cuts?

There's no reason why they should even try.

Photograph: Getty Images

Matt Yglesias asks what could be an existential question for conservatives on both sides of the Atlantic:

This is the question for John Boehner and Paul Ryan whenever they do unveil their balanced-budget plan: Why not make taxes lower instead of balancing the budget? The budget will, presumably, cut spending down to a level that conservatives think is appropriate. Say that sums up to 18 percent of GDP. Well if you're spending 18 percent of GDP and 18 percent of GDP is the right amount to spend, then why is it better to raise 18 percent of GDP in taxes rather than raise 16 percent and borrow the rest?

For the time being, in Britain and America, rhetoric about "getting the deficit under control" and about "shrinking the size of the state" are pointing in the same direction. Both are reasons for the massive spending cuts which the Conservatives and Republicans have attempted to enact.

Most of the attacks on the false connection between those two arguments have been focused on the "shrinking the state" part of the equation. That is, questions like "if we're trying to reduce the deficit, why aren't we raising taxes on the rich/on bankers/on financial transactions" are appropriate for exposing the drive for deficit reduction as a sham, driven largely by ideology.

But what if, instead, we accept — hypothetically — that the size of the state had to be shrunk. Eventually, spending would be "under control", whatever that means for them, and the choice would become whether taxes ought to be at the same level. Why, all things considered, would it be bad if they weren't? Yglesias asks:

Is it because a 2 percent of GDP budget deficit would be inflationary? Is it because an inflation-targeting central bank faced with a 2 percent of GDP budget deficit would be forced to peg short-term interest rates at a high level? What's the problem, exactly, that the budget balancing solves once we've stipulated that spending has been cut to an appropriate level?

Of course, in the political world, we would be unlikely to get such a clear answer to that question. Rhetoric about a "maxed-out credit card", "paying off the country's mortgage" or "unsustainable budget deficits" — where "sustainable" is never defined — dodges the fact that the macroeconomics of small persistent budget deficits in a country which controls its own currency are relatively settled: it's fine. And chances are that if the Conservatives do manage to get the deficit down, and cling on to power through 2015, then they will do the obvious thing, and enact deficit-funded tax cuts.

But getting a straight answer to that question from the economically minded people who call for swingeing spending cuts now would be interesting indeed.