Fear of lending to banks is rising again in Europe, as even a 750 billion euro zone rescue package proves not enough to stem fears that the banking system will prove the weak link when southern European nations can’t meet their obligations.

Strikingly many European and British banks are now being forced to pay more to borrow money in the interbank markets than before the joint European Union, International Monetary Fund and European Central Bank package was announced two weekends ago.

That deal, which should insulate highly indebted countries such as Greece, Spain and Portugal from funding pressure for the next two years or so, was effective in driving down the extra interest those countries had to pay to borrow as compared to Germany. Tellingly, it was less effective, even counter-productive, in restoring calm to the markets in which banks fund their short-term borrowing needs.

While the mutual distrust is still far less than the utter panic during the crisis following the collapse of Lehman Brothers in 2008, it is very significant that the bailout of the weak links in the euro zone is having far less of a multiplying effect than earlier infusions of cash and liquidity into solvency shortfalls.

It may be simply a passing tremor. It may be a result of structural weakness in the euro zone, as investors bet that when push comes to shove a politically fractured Europe will find it impossible to agree on how to underwrite and fund the rescue of banks facing losses if Greece and its peers default.