Just a day before polls opened in the New Hampshire primary, former South Bend, Indiana, mayor Pete Buttigieg appeared at a town hall to convince residents of Nashua why they should vote for him. When a member of the audience asked how important the federal deficit is to the presidential candidate, Buttigieg replied that he believed it was "very important" even thought it's "not fashionable in progressive circles."

He went on: "I think the time has come for my party to get a lot more comfortable talking about the deficit. Because right now we got a president who comes from a party that used to talk a lot about fiscal responsibility, with a trillion-dollar deficit, and no plan in sight for what to do about it…This should concern progressives, who are not in the habit of talking or worrying too much about the debt."

That comment generated some strong reaction. New York magazine's Eric Levitz called it "fiscally irresponsible," and Paul Waldman at the Washington Post wrote that Buttigieg was "playing with fire—and playing right into Republicans’ hands." The American Prospect magazine was perhaps the most incendiary though, labeling Buttigieg "Austerity Pete."

How did we get from talking about the deficit to austerity though? In politics and economics, austerity refers to policies that governments use to lower public sector debt. Typically, this involves cutting social service programs, hence the "austere." But it can take a lot of different forms, like raising ride prices on public transit or cutting the pensions of public employees. It's a commonly used tool for reducing national debt, but it's not very effective just on its own. Bill Clinton, for example, famously balanced the national budget during his presidency, and while he did impose spending restrictions in his 1994 budget, the surplus generated under his administration came largely from new taxes on high earners combined with the dot-com bubble, which produced a lot of unexpected tax revenue.

But dramatic cuts in public spending can also be disastrous. The Greek debt crisis is probably the highest profile example. In 2009, Greece was struggling with a massive budget deficit, and the European Union agreed to bail the country out. In exchange for over $330 billion in aid, Greece was forced to implement deep austerity cuts that actually caused the economy to spiral, leading to more job losses, further drops in tax revenue, and even greater pubic debt. In addition to hamstringing the Greek economy, the austerity program also unleashed such chaos in the lives of every day people that Golden Dawn—a neo-fascist party with a modified swastika as its emblem—became the country's third largest political party by running on an anti-austerity and anti-immigrant platform.

Austerity is one of the ideas that economist John Quiggin calls, "zombie economics," concepts that are discredited yet somehow keep cropping up again and again despite the rationale for it being "absurd on the face of things." Nobel laureate Amartya Sen said in 2015 that austerity had "deepened Europe’s economic problems, [and] it did not help in the aimed objective of reducing the ratio of debt to GDP to any significant extent." And another Nobel laureate economist Joseph Stiglitz has said that in light of its failures, "It is remarkable that there are still governments, including here in the U.K., that still believe in austerity."

Right now, even Republicans aren't terribly concerned with the national debt. That's according to none other than Mick Mulvaney, Donald Trump's acting chief of staff and former head of the Office of Management and Budget. In audio of a speech on Wednesday night obtained by the Washington Post, Mulvaney said, "My party is very interested in deficits when there is a Democrat in the White House. The worst thing in the whole world is deficits when Barack Obama was the president. Then Donald Trump became president, and we’re a lot less interested as a party."