Having one leading politician murdered could be labelled an accident. Having two leading politicians murdered (in the case of Sweden: Olof Palme and Anna Lindh) has a taste of carelessness to it.
What to do about it?
The usual response has been an increase in protection of leading politicians – which in its turn also cuts off political leaders from everyday life. No improvised trips to the cinema. No quick visit to the local supermarket at 9 PM. And of cause taking the commuter train to the Chancery is completely out of question.
In an interesting post at VoxEU (ok, are there any posts at VoxEU that are not interesting? Political Science could use a similar outlet for research-based comentry, even if Henry Farrell is doing his best), Bruno Frey from the University of Geneva uses a simple economic model to argue that the social cost of protecting politicians always outweighs the individual benefits.
This view of democratic systems is also very interesting:
A democracy is characterized by an orderly change of power, even if the political leader is killed. Political decisions depend little on the personality of politicians, because they are constrained by the citizens. In a pure competitive democracy, the two competing parties are obliged to pursue the same policy (in the median of the voter distribution), and the politicians have no discretionary room. Killing a political leader would have no consequence and therefore would not be undertaken. (Before you attack Frey, please note that he makes a reservation for mentally disturbed people)
Thought-provoking, even if you may not want to abolish all security measures.