But Robin never made that error. Those opposite, squirming under the lash, convinced that he frequently manufactured his feelings, were waiting for the moment to dismiss him as a master of flouts and gibes and sneers. He never gave them the chance. The choice of words, the rhythm of his sentences, the ruthless tautening of his arguments until they became the bowstring of anger: formidable. This was of great value to his party during the long years of opposition.
Less so in government, however. There, he displayed the defects of his qualities. The speed with which he could whip together a prosecution brief deluded him into complacency. He did not realise that working out government policy in a major department of state would require hard, sustained effort: an endless grappling with complexity.
There is an instructive anecdote. In the mid-90s, when Robin Cook was shadow Health Secretary, a left-wing journalist complained to him that Labour did not have a health policy. "You're right," he replied. "So what are you going to do about it?" "Nothing," Cook answered, enjoying his visitor's startled dismay. "You know the position, and I agree. But did you see the latest opinion poll? It appears that 80 per cent of the voters think that Labour has the best policies on health. If they are happy with our policy, so am I."
There was also a fundamental problem. Until the mid-80s, Cook had coherent beliefs. In economics, he was a socialist; on foreign affairs, he was opposed to Nato, the EU and the nuclear deterrent. He was always ready to make excuses for the Soviet Union and find fault with the Americans.
Along with others of the same persuasion, he then realised that, if there were ever to be another Labour government, such views would have to be abandoned. They were, but they were never replaced. Robin Cook never thought through an alternative world view. Although that may not have impaired his critical powers, it did not assist his constructive ones.
He was not a good Foreign Secretary, and his incompetence could be embarrassing - as when he asked the Romanian Foreign Minister whether his country had a common border with Greece. Cook seemed more comfortable once he returned to the back benches. He could not deploy all his old vituperation; his party was in office. But even when using the flat of the sword instead of the blade, his interventions were feared.
There is a paradox here. It might seem a bizarre leap to move from Robin Cook, gleeful scourge of successive Tory front benches, to the Tory party's current problems, yet there is a connection. Why could Cook make negative campaigning work so well for Labour, when the Tories have consistently failed to do so?
The contrast cannot be explained merely by reference to Cook's superior talents. In William Hague, the Tories have a parliamentary performer who is almost Cook's equal when it comes to mockery. Hague was forever landing hits and witticisms on the Blair government; much good it did him. Indeed, the Hague experience has persuaded many Tories that knocking copy never works for them. However clever it may seem on paper, however many laughs it arouses in the Chamber, it merely reinforces the public's impression that the Tories are the nasty party.
Yet recent developments have also reinforced many Tories' frustration at their inability to use adversarial politics to expose both the Government's administrative incompetence and its moral failings. For the past few years, the Tories have drawn attention to the collapse of the asylum system, the porousness of Britain's borders, the huge number of illegal immigrants, and the role of over-generous social security arrangements in attracting the wrong kind of immigrant.
Many Tories also warned that Labour's Human Rights Act would undermine any government's ability to protect the country's safety. Although the concept of human rights imported vagueness and confusion into our legal system, there was one point on which we could be certain.
The judges, who were taking increasing numbers of political decisions, would always ignore two points: that apart from the right to life, no right is more important than the right to order, and that no right - including the right to life - can be securely enjoyed in its absence.
Asylum, immigration, human rights: the Tories uttered the warnings, and even some fellow Tories gave them a cold reception. There was a lot of high-minded unhappiness with the tone; it all sounded uncharitable, unfeeling, harsh.
Yet today, almost everyone is expressing alarm about weak border controls. Tony Blair himself agrees that the Human Rights Act might have to be amended. He makes it clear that, for him, however much human rights judges and lawyers might disapprove, salus populi suprema lex.
So what is left for the Tories? To insist that they were right all along? Everyone seems too impressed by Blair's performance to refer back to the historical record. Convinced of the justice of their case, equally and bitterly convinced of the injustice of the public's response, Tory spokesmen are left carping on the sidelines.
The same is true on Europe. For years, Blair seemed determined to lead Britain towards federalism. He wanted to abolish the pound. He was bent on signing up to the constitution. It seemed as if, for once, he had a core belief: a Heathite vision of a European destiny - which would also win him his place in history.
It failed. One might have thought that this would affect Blair's morale. To most politicians, the loss of a core belief would be of some consequence. In this case, not at all. Anyone listening to Blair could be forgiven for concluding that he had always been a Eurosceptic.
So here again, the Tories do not know how to respond. They are dealing with a politician who not only reinvents himself from day to day, but also reinvents his past, always smiling while he does so, thus ensuring that his Tory critics will sound like mean-spirited pedants. We have not seen the last instalment of Tony Blair's political genius.
We have, alas, seen the brutally premature end of Robin Cook's career. For once, the awed tributes are wholly justified. It is hard to imagine the Commons without him.Reuse content