For all his talk of "listening to the Greeks", Tsipras neglects to mention leaving the euro would require even more draconian austerity because Greece would have to close its primary budget deficit overnight.

CNN: Opinion: Greeks prefer Europe to its own politicians

With those changes, we reckon Greece would need to cut its primary budget deficit (ie, excluding interest costs) by 12 percentage points to cap its debt burden a slightly less fierce adjustment than in our first simulation.

ECONOMIST: Bailing out Greece

Greece has missed plenty of budget targets, but over the past two years, the government has cut its primary deficit the budget deficit excluding interest payments to 2.2% of GDP in 2011 from 10.6% in 2009.

WSJ: Greece Deserves Credit, but Debt's an Issue

What matters here is not the total budget deficit but the primary one.

FORBES: The Real Greek Solution: Democracy

Both plans aim to improve the primary deficit, with President Obama nearly balancing the budget by the end of the time-window (2022).

FORBES: Fiscal Cliff Should Help Obama And Paul Ryan Find Common Ground On Budget

And it is often forgotten by Republican leaders that this is the case, that some of the very Republican leaders in office now who claim as their objective deficit reduction, primary objective, presided over enormous budget-busting legislation in the previous administration.

WHITEHOUSE: Press Briefing by Press Secretary Jay Carney,

Are you going to ask for it to be raised big enough to the point where you get to the year where in your budget you get to primary balance, which I think is 2017 -- which is a zero deficit -- running zero yearly deficits?

WHITEHOUSE: Press Briefing