State run banks already now play a big role. Sparkassen, Landesbanken and the KfW make up a third of German banking or so. And judged by the Landesbank performance, I doubt that state owned banks will do better than private banks.
Postbank is privatised and sold to Deutsche Bank, but the biggest shareholder of the Post is still the federal gov't. And the Post got 10% stake in Deutsche (Germanies biggest bank, balance 2007 2.020 trillion Euro) for the deal.
The second largest German bank, the newly fusioned Commerzbank with Dresdener bank (together a balance of 1.1 trillion) has now a 25% federal gov't stake, as Commerzbank couldn't afford the fusion and needed federal money.
The third largest bank is already LB-BW with a balance of 0.44 trillion.

For the law. Yes, it is ridiculous, a bank that needs public money to survive obviously has zero value, and therefore nationalisation doesn't take away anything from anybody. But beside every economic debate being ideological, in Germany every economic debate is dominated by totally uninformed people.

I doubt, the law will actually be used, and if, for sure in exactly one case, the one of HRE. The only other system relevant bank, in which the state doesn't already have controlling share is Deutsche, and that bank is too big to be nationalised. You really don't want their liabilities as national debt, when it turns out, they have accounting as good as Lehman's. Then better a normal insolvency.

In general it maybe more interesting, if the goal is, to keep all those stakes in the banks, or if in a couple of years everything is privatised again. That's not a done deal yet.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers