You gotta cover your ass

Here is Tony Blair verbosely blabbering away again.
On this significant occasion is making sure his exalted ass is covered:

http://timesofindia.indiatimes.com/world/uk/Former-UK-PM-Tony-Blair-says-Iraq-crisis-not-his-fault-

urges-action/articleshow/36607424.cms

Question:

Are you really interested in how he covers his ass?

Question 2:

So why does he find it necessary to do so.