From The New Yorker, July 11 & 18, 2011, "The Financial Page:  Dodger Mania," about corruption and tax cheats in Greece:

Greek citizens also have what social scientists call very low "tax morale."  In most developed countrie, tax-compliance rates are much higher than a calculation of risks would imply.  We don't pay our taxes just because we're afraid of getting caught; we also feel a responsibility to contribute to the common good.  But the sense of responsibility comes with conditions.  We're generally what the Swiss behavioral economist Benno Torgler calls "social taxpayers":  we'll chip in as long as we have faith that our fellow-citizens are doing the same and that our government is basically legitimate.  Countries where people feel that they have some say in how the state acts, and where there are high levels of trust, tend to have high rates of tax compliance.  That may be why Americans, despite being virulently anti-tax in their rhetoric, are notably compliant taxpayers.