"An economy is not like a household. A family can decide to spend less and try to earn more. But in the economy as a whole, spending and earning go together: my spending is your income; your spending is my income. If everyone tries to slash spending at the same time, incomes will fall — and unemployment will soar." -- Paul Krugman.
When economies aren't growing and unemployment is high, the solution is not austerity but more stimulus (spending), he says. The 2009 stimulus is what prevented another Great Depression and a decade or more of no growth or economic contraction.
The time for fiscal austerity is when economies are expanding on their own steam. The US Congress on January 1, 2013 took small steps towards austerity, eliminating the two-year payroll tax holiday (for worker contributions to social security), and raising taxes from 35% to 39% on households earning more than $400,000 a year. Congress also took stimulative action: it extended unemployment benefits to 99 weeks in partnership with states (depending on a state's unemployment rate). The CBO estimates this action will expand jobs by 300,000. Indeed, the US economy is still projected to grow by about two percent in 2013, barring unforeseen economic catastrophe and foreseeable (and avoidable) political catastrophe like Congress refusing to raise the debt ceiling and pay the nation's bills on spending they've already authorized.