Although a bit of a deviation from the primary topic, I would be inclined to say that Obama is our Achilles Heel.
Some folks have taken that thought to another level and have suggested that Obama is symptomatic of a deeper problem in America.
For example, check out the following brief article published (supposedly) in a Czech Republic Newspaper (Prager Zeitung - 4/28/2010)...
“The danger to America is not Barack Obama but a citizenry capable of entrusting a man like him with the Presidency. It will be far easier to limit and undo the follies of an Obama presidency than to restore the necessary common sense and good judgment to a depraved electorate willing to have such a man for their president."The problem is much deeper and far more serious than Mr. Obama, who is a mere symptom of what ails America . Blaming the prince of the fools should not blind anyone to the vast confederacy of fools that made him their prince. "The Republic can survive a Barack Obama, who is, after all, merely a fool. It is less likely to survive a multitude of fools such as those who made him their president.