That said, the question remains: how to strike the balance between free speech and mutual respect in this mixed-up world, both blessed and cursed with instant communication? We should not fight fire with fire, threats with threats.
Nuclear proliferation - the proliferation of WMDs altogether - is one of the greatest dangers of our time.
The key to the survival of liberty in the modern world is the embrace of multiple identities.
Europe is a woman, now middle-aged, who has already had a number of heart attacks and is currently experiencing the biggest health crisis of her life, but one that need not be fatal.
The first job of the historian and of the journalist is to find facts. Not the only job, perhaps not the most important, but the first. Facts are the cobblestones from which we build roads of analysis, mosaic tiles that we fit together to compose pictures of past and present. There will be disagreement about where the road leads and what reality or truth is revealed by the mosaic picture. The facts themselves must be checked against all the available evidence. But some are round and hard--and the most powerful leaders in the world can trip over them. So can writers, dissidents and saints.
If you had said to anyone in 1945, at the end of the Second World War with the continent it ruins, that you could have a European Union of 28 member states stretching from Portugal in the West to Estonia in the East, all of them more-or-less liberal democracies - they wouldn't have believed you.
There is already a generation of European graduates who feel they have been robbed of the better future they were led to expect. They are members of a new class: the precariat.
So what were Europeans telling their leaders? The general message was perfectly summed up by the cartoonist Chappatte, who drew a group of protesters holding up a placard shouting "Unhappy" - and one of their number shouting through a megaphone into the ballot box. There are 28 member states and 28 varieties of Unhappy.
Developments in information technology and globalised media mean that the most powerful military in the history of the world can lose a war, not on the battlefield of dust and blood, but on the battlefield of world opinion.
In a democracy it is ultimately for us, the citizens, to judge where to place the balance between security and privacy, safety and liberty. It's our lives and liberties that are threatened, not only by terrorism but also by massive depredations of our privacy in the name of counter-terrorism. If those companies from which governments actually take most of our intimate details want to show that they are still on the side of the angels, they had better join this struggle for transparency too.
To be in Florence is to reflect on Europe's intricate diversity - and its lost creativity.
Every step that produces a single job for a currently unemployed European should be taken. Every centimetre of red tape that puts someone out of work must be torn up.
What is the elephant in all our rooms? It is the global triumph of capitalism. Democracy is fiercely disputed. Freedom is under threat even in old-established democracies such as Britain. Western supremacy is on the skids. But everyone does capitalism. Americans and Europeans do it. Indians do it. Russian oligarchs and Saudi princes do it. Even Chinese communists do it... Karl Marx would be turning in his grave. Or perhaps not, since some of his writings eerily foreshadowed our era of globalised capitalism. His prescription failed but his description was prescient.
Well, that's the way democracy works. We have to build this Europe with the material we have at our disposal. And this material is national democracy.
Starting from the ruins of the Second World War, we - all Europeans said, after centuries of fighting each other, we're going to build permanent arrangements in which peace between European countries is secured, freedom is secured, and growing prosperity. And that's what we have done over the last 70 years.
Europe's biggest problem is its success.
The trouble is that privacy is at once essential to, and in tension with, both freedom and security. A cabinet minister who keeps his mistress in satin sheets at the French taxpayer's expense cannot justly object when the press exposes his misuse of public funds. Our freedom to scrutinise the conduct of public figures trumps that minister's claim to privacy. The question is: where and how do we draw the line between a genuine public interest and that which is merely what interests the public?
I'm a historian by training and by conviction. And so the thing that has throughout informed my thinking about international relations is history. I think, for example, the reason that I was perhaps able to see sooner than some others that the Soviet Empire in Eastern Europe was decaying--if not disintegrating--was that I came to it through history and through Germany, rather than through Sovietology and through Moscow. And therefore the starting point was that no empire in history has lasted forever, and this one won't either.
I have a dreadful feeling in my bones that future historians may write of the May 2014 elections: "This was the wake-up call from which Europe failed to wake up."
The whole project of European Union is one in deep trouble.
The main problem with American power is not that it is American... No, the main problem with American power is the power itself. It would be dangerous even for an archangel to wield so much power.
As one looks back, one sees that the fall of the Berlin Wall opened the door to three developments - the Eurozone, which was crafted around German unification, the free movement of peoples within Europe, particularly people from the new democracies of Eastern Europe, and, more broadly, it opened the door to globalization.
The Eurozone has clearly gone spectacularly wrong, pulling down all the continental economies.
People feel that European institutions are remote and bureaucratic, run by shady cosmopolitan elites. Britain is not absolutely exceptional because if you look at the opinion polls, those sentiments are now quite widespread also in continental Europe.
I find Chinese debates about their political system domestically, but also about China's claims in the international system, to be among the most original and surprising and exciting of our time. The starting point is a system that none of us had anticipated, which I call Leninist capitalism, but also obviously because it is the most important emerging power. The question of China's relations with the United States in particular, and the rest of the world in general, is the question of war and peace in the 21st century.
