Make Us Thrifty, But Not Yet

Yglesias comes out as another liberal finding reasons not to tackle the long-term debt now:

The budget deficit isn’t currently a problem, but it almost certainly will be in the future and that’s when congress will act to deal with it [...]  It would be wise and just and moral for the 112th Congress to pass a judicious long-term debt reduction program, but it doesn’t seem even remotely realistic. Is there any precedent for a country doing deficit reduction pre-emptively in the way everyone seems to be suggesting we should?