The shepherds of the nation in Jeremiah's time were the kings of Judah, who were both the spiritual and political leaders of their people. They had not only failed to protect their flock through negligence or weakness. They had done active harm by destroying and scattering it, which implies that their policies were wicked and reckless. Their conduct brought God's judgement down upon their heads.
Why does Jeremiah go on to say that God drove the people into exile? Was this for their own protection, to save them from further harm? Or was God angry with the people for putting up with such poor leadership? Who are the leaders of the nation today? In a democratic country, and a democratic church, is it we - the people - who have failed to show proper vision and obedience, or can we still blame other people, politicians and church leaders, for our problems?
One of the concerns which people had when democracy was first introduced was that people would make ill-informed and misguided decisions, egged on by leaders who were happy to sell them lies and half-truths. The only way to avert that danger in a democracy is for people to have good, solid values and allegiances, not shifting and deceitful ones.
The Advent promise is that God will raise up new, more capable leaders who really do care for the nation, and who know the difference between right and wrong because they are guide by a king who rules with wisdom, righteousness and justice. We could call it an era of 'no more spin'!