The modern economy utterly depends upon credit, whether it's to allow individual students and households acquire an education or a home, an entrepreneur or large company to finance the creation or expansion of a business, or a sovereign state or other public entity (school district, county, etc.) to build infrastructure and/or provide social services. When flows of credit dry up, economic life dessicates, too.
All macroeconomic crises are credit crises to one degree or another. Never has this been more obvious than during the extended "recession" in which the world—particularly North America and Europe—has been mired for several years. Mortgaged home owners "underwater" and facing imminent foreclosure. Students saddled with debt that they'll be repaying long after graduation day. The State of California, like most of its peers in the USA, stuck in a repeating "Groundhog Day" loop of perennial impending budget disaster. The list of credit crunches goes on and on and on.
And then there is Greece. Sure, Spain, Ireland, perhaps even Italy sometime soon: these Euro-zone governments face some pretty daunting fiscal challenges themselves—and the United States isn't exactly a model of sustainable public finance either. But no sovereign debt crisis is as salient right now as Greece's, to the point that investors around the world effectively expect its government to go bankrupt; already agencies such as Standard and Poor's and Moody's have lowered their credit ratings of Greece to "junk bond" levels. This isn't good, and it threatens not just the Euro monetary zone but could send shockwaves through the entire global economy. All of this makes for very depressing summer reading, the source of much hand wringing and finger pointing among leaders and pundits, as well as for some very understandable anger on the streets of Athens and other Greek cities.
It is indeed very hard not to be pessimistic about our economic prospects. And that's the catch. As FDR famously reminded us during the depths of the Great(est) Depression, "the only thing we have to fear is fear itself." Credit is a funny and fickle thing, prone as it is to self-fulfilling prophecies. Optimism can snowball into "irrational exuberance" and create enormous bubbles of wealth and overconsumption. An infectious pessimism, though, can melt that snowball—burst that bubble—no less quickly as interest rates spike, revenues collapse, and opportunities to restructure/refinance debt disappear.
No, we can't simply "hope" our way out of the current economic crisis. Like any good hangover, this is a time for sober reflection upon our earlier excesses—reflection that informs sincere reforms to the way we generate and spend money. But if Greece (or California, or the USA) is to be saved, as the esteemed Columbia University economist Jeffrey Sachs argues, it will be through leadership and policy founded upon a committed and confident optimism that dares to promise—sincerely promise—what most don't presently believe possible: Greece can and will pay off its debt, especially if stronger nations pledge their support and thus hold back the economic vultures poised to feed on and profit from our pessimism.