It is especially important to encourage unorthodox thinking when the situation is critical: At such moments every new word and fresh thought is more precious than gold. Indeed, people must not be deprived of the right to think their own thoughts.

You have no right to criticise Russia over Chechnya.

I refer to calls for humanitarian intervention in the affairs of another state - a new idea, this - even when they are made under the pretext of defending human rights and freedoms.

International terrorism is throwing down a challenge, and not just to Russia.

As many people have chronicled, the decision to fight in Vietnam was a years-long accretion of step-by-step choices, each of which could be rationalized at the time. Invading Iraq was an unforced, unnecessary decision to risk everything on a 'war of choice' whose costs we are still paying.

From horrific incidents of police brutality and complicity in indiscriminate attacks by triads on citizens to arbitrary mass arrests and the banning of demonstrations, the government has employed nearly every weapon in its war chest to intimidate Hong Kongers into silence and to suppress their popular struggle for democracy and freedom.

Quite frankly, Russian aggression in Ukraine and its illegal occupation of Crimea remind us that we still have a good deal more work to do to guarantee the strategic vision of a Europe whole, free and at peace.

I was not able to stop or slow down the Vietnam War.