Russia is going to have a very hard time directly attacking the Eurozone without also hitting NATO home soil - which through Article 5 would also pull in plenty of non-Euro countries, including the United States. Besides, shoveling never-ending piles of cash into the furnace of the War Machine doesn't seem to have hurt the dollar?

As to shifting politics: The EU is famously extremely hard to move.

The European Council decides the political direction and consists of the heads of state of the member countries; the European Commission is the executive cabinet and needs buy-in from the Council of the European Union and the European Parliament; the Council of the European Union is made up from ministers of the member states and each member state has a veto right on all foreign policy proposed by the European Commission; the European Parliament's members are directly elected through independent elections in the individual member states with proportional representation, and any policy proposed by the European Commission also needs a majority here; the Court of Justice of the European Union's General Court oversees this and is composed of two judges appointed by each member state for a renewable six-year period and reviewed by an independent committee.

In other words: nothing gets done fast, and nothing gets done without buy-in from a lot of people with very opposed political goals. Quite different from a country like, say, the United States, where the loser of the popular vote routinely becomes president, is handed God-Emperor levels of power, and is virtually impossible to unseat - leaving the foreign policies of a nuclear superpower to be decided by how a single person felt when he stepped out of his bed this morning.