A few weeks ago, the CDU chairman Friedrich Merz described a possible exclusion of Russia from the international payment system Swift as a "nuclear bomb for the financial markets".
The Russian attack on Ukraine makes this choice of words seem macabre today.
Nevertheless, it still has a kernel of truth.
At least since the financial crisis of 2007/2008, it should be undisputed how much exogenous shocks can endanger the stability of the financial markets faster than anyone would like to imagine.
Whoever cuts Russia off from Swift must know that it will have repercussions on European and also on German banks - and that Western creditors are threatened with defaults if Russian debtors are cut off from the international markets.
Last option - for good reason
In this respect, there are reasons why Germany only wants to exclude Russia from Swift as a last resort.
It is also not dishonorable that the federal government is keeping a very close eye on the effects of these severe sanctions on the German economy and the German financial system and is therefore hesitating.
Of course, the damage has already been done, as reactions from other EU countries to Germany's hesitation show.
It is certainly easier for those states to demand particularly severe sanctions because their economy (supposedly or actually) is less affected than Germany's.
But the accusation from several EU partners that Germany wants to make Swift the "new Nord Stream 2" shows how dangerous Berlin's current behavior is.
It's not just about Germany's credibility in the EU.
Above all, the question is whether the federal government is willing to follow up its cheap words about a “decisive response” by the EU to the Russian attack with action.
Yes, the Russian Swift ban is not something to be decided lightly.
But the federal government must not duck around it.
Friedrich Merz got the formula right, that this step must not fail because of Germany.