The ironclad partnership between France and Germany has been the most frustrating geopolitical reality for Britain since the 1950s. For hundreds of years, the British worked to maintain a European balance of power which in effect gave them the ability to tip the balance for or against any other power.The Franco-German entente ended that; the two strongest powers in western Europe banded together, marginalizing the UK as Germany and France built the EU to suit themselves.Now the crisis over the euro has turned into a struggle for the mastery of Europe between France and Germany. As I wrote in the Wall Street Journal yesterday, the fundamental question is whether Germany will impose its model of governance (strict central banking in the service of hard money and low inflation) on the eurozone, or whether the softer, more politically sensitive and inflation tolerant Latin model will prevail.Another story in the Journal this morning has an eye-popping possibility: that Germany and Britain could be cooking up a deal behind France’s back that would throw British support to German plans for the Continent in exchange for German acceptance of key UK demands, safeguarding London’s financial industry, giving the UK some opt outs from European regulations it doesn’t like plus some budget relief, and ensuring that non-euro states won’t be frozen out of future EU plans.The interesting thing is that none of these demands, vital as they are to the British, pose insurmountable obstacles to the Germans. The French demand that the ECB become a lender of last resort for troubled European governments and banks, on the other hand, is impossible for the Germans to accept. Between the two, the rational German choice may well be to cut a side deal with the British.The conventional view is that Britain and Germany have irreconcilable views on what Europe should look like — and that the British are so suspicious of German power that they will never agree to a “German Europe”. This is by and large true; the Germans do want a strong political union to emerge in Europe, and the British instinctively fight that idea. This article by the noted scholar and observer Timothy Garton Ash in the Los Angeles Times does a good job of showing how deep the gaps between the two countries are.But Germans can be very pragmatic; offering substantial concessions to Britain complicates but does not destroy the realization of Germany’s vision. Letting France write the economic laws of the eurozone turns a German dream of European integration into a nightmare of inflation and disorder — at least as many Germans see things.It won’t be that easy. Germany still needs treaty changes to create the kind of economic union among the eurozone countries it wants; France and its allies can block those treaties. But Germany has some powerful cards in its hands: it can offer or withhold the financial aid that the troubled Club Med economies urgently need. Since the French banking system cannot withstand a Club Med meltdown, Germany has a lot of leverage with France also.In the past, both Germany and France have toyed with Britain from time to time as a way to gain leverage against one another, but at the end of the day, the British have never been able to drive a wedge between the two main drivers of the EU. There’s still a good chance that Germany is using Britain to put pressure on France and will drop the UK like a hot bratwurst if France caves — but the ECB dispute is so deep that France may not cave.For investors, and for spectators trying to figure out if the European mess is going to trigger Global Meltdown Round Two, the message is grim. The Germans are playing hardball, which means no quick solution to the euro mess is in sight.For Britain, however, this is a rare opportunity. Breaking the Franco-German grip on the EU system would be the biggest victory for Britain in a very long time and it would open a new and interesting era in European politics. The Cameron government should do its best to reach an agreement with Germany; opportunities like this do not come up every week and if ever there was a time for a British prime minister to think clearly, creatively and boldly, this is it.