http://voices.washingtonpost.com/ezra-klein/2010/05/galbraith_the_danger_posed_by.html
If you have some time to stomach some of the worst, incoherent arguments around regarding government spending I’d recommend giving this a read (and some of the comments have some “gold” too).
"As usual, James Galbraith is one of the few rational voices when it comes to discussing the budget deficit. The US government like all sovereign governments can always spend more than it earns – continuously and indefinitely – because the concept of “earning” is redundant. Unlike a household or a corporation, the sovereign government doesn’t need to earn to spend. That is a fundamental part of having a fiat currency system. This is NOT the case in Greece, or any other Euro zone country, because they are users of their currency, not issuers (which is done the by European Central Bank).
The US Federal Government might hide behind institutions (like debt-issuance mechanisms) and rhetoric (like we are running out of money, as our President often writes) but the operational reality is that behind all these smokescreens – the US government is not revenue-constrained."