Metatone:

Some level of the financial crisis can be laid into the Basel agreements that wrote ratings agencies into the process - i.e. AAA is safe for pension funds, etc.
This ECB rule is the same mistake writ large. I understand the urge to invoke an outside agency on country ratings - it helps pretend things are "not political" - but the reality is that the ratings agencies are dominated by an ideology that is in fact very political.

Alas, the Brussels-Frankfurt Consensus is just another genetic mutation of the Washington Consensus, so the ECB is quite comfortable with the political ideology of the ratings agencies...

Migeru

For definiteness, here is the definition of a rating agency in the Basel accords: (source: Bank of International Settlements, Basel II: International Convergence of Capital Measurement and Capital Standards: A Revised Framework - Comprehensive Version Part 2: The First Pillar - Minimum Capital Requirements)

...

The observation is usually that no agency satisfies these conditions. So, national supervisors (that is, central banks) would be well in their rights to decree that the institutions they supervise are not required to use agency credit ratings to risk-weight their assets for regulatory capital purposes.