There can only be relief among America’s adversaries and her friends at the resignation of President Nixon. It became obvious weeks ago that even if Mr Nixon was to survive an impeachment by one or two votes, he would have no authority to push his policies through Congress. He had become a duck with two lame feet. The uncertainty and confusion in the capital of the Western world had continued for too long, and it was not only America’s allies who were concerned by the vacuum. Both the Soviet Union and China were unhappy with such an unstable situation. Neither was able to make intelligent predictions about policies.

With his statement earlier this week – in essence a guilty plea to the impeachment charge of obstruction of justice – Mr Nixon was only left with a choice of resigning or being removed by Congress. With the release of the latest White House tapes it is clear that Mr Nixon was going to be impeached by the House of Representatives and convicted by the Senate. The tapes proved that in spite of his persistent denials, Mr Nixon had not only known about the Watergate cover-up but ordered it.

At the end even his defence lawyer was speaking of the President’s impossible position. Rearguard holding action followed rearguard holding action but in the end by a mixture of luck, persistence, and hard work, sufficient truth has been extracted to demonstrate that Richard Nixon is not fit to be the leader of the Western World. To his overseas constituents the most frightening aspect of Watergate was the glimpse they were given into the operation of the Nixon White House. That the man who is in charge of the US nuclear arsenal was surrounded by men without scruples or political integrity was already well known. What was not known until the release of the tapes was the width of their amorality, the cheap quality of their advice, and the total disregard for law which permeated the White House.

A President has several constituencies which sustain him. He can govern if he has the support of the people even if official Washington has lost faith in its leader. He can govern if the people have lost faith but official Washington understand his predicament and lend support. But, with his lies and “high crimes and misdemeanours,” Mr Nixon has destroyed the faith of the people, the officials, Congress, and his own Republican Party. By withholding the truth of the cover-up from even his closest friends, he has lost the support of the small coterie of Congressmen prepared to be loyal supporters - and not just lost their faith and respect.

Mr Nixon has exposed both the perils and the strengths of the US political system. That the leader of the country should be able to use the institutions of Government – the FBI, CIA, and the Inland Revenue – for his own political ends is one of the many weaknesses Watergate has exposed. But that other institutions could cry “halt” and set into process an impeachment procedure that has paralysed the President but allowed Government to continue is an indication of the nation’s strength. That the procedure has still worked even though designed 200 years ago when speed was much less important is all the more remarkable. Lord Bryce thought the procedure involved such “heavy artillery” that it was unfit for ordinary use. President Nixon has shown that in extraordinary times it can be used.

Tourists reading President Nixon resignation news, 8 August 1974. Photograph: Bettmann/Bettmann Archive

Mr Nixon has some achievements to his credit which in later years will make his presidency look somewhat less tarnished than it does today. His major accomplishments have been in international affairs where, with Dr Kissinger’s help he removed the blinkered anti-communist ideology which had so hampered American foreign policy in the past. He ended the isolation of China, gave Mr Brezhnev an incentive to be more accommodating with the West to avoid two cold fronts, made some headway in strategic arms limitations, and secured better relations with the Soviet Union. Mainly because of Dr Kissinger’s unflagging energy there is a much greater chance of peace in the Middle East. Inflation in the US has been under better control than many Western countries partly because he freed his country from an overvalued fixed-rate dollar.

There were mistakes. Allies were ignored. Both Europe and Japan were forgotten in the heady atmosphere of the Sino and Soviet summits. It took four years for Mr Nixon to withdraw his troops from Vietnam. Lack of preparation and loss of support at home have slowed up Salt II.

But it was in domestic affairs that Mr Nixon failed to give effective leadership. His civil rights programme was a disgrace with political pressure applied to civil rights officers to halt school desegregation even where it could have been accomplished peacefully. Poverty bills were vetoed, two of his nominations to the Supreme Court were so unworthy that they failed to pass the Senate, and he tried in various ways to muzzle the press.

Vice-President Gerald Ford has not distinguished himself since relieving Spiro Agnew. He has had a difficult role attempting to be loyal to both his party and the President who appointed him. At first it looked as though his loyalty would swing back and forth but in recent weeks Mr Nixon could not have had a more loyal supporter. The handover should not create drastic changes in foreign policy. Dr Kissinger has been at pains this week to stress the continuity of US foreign policy. Vice-President Ford has said he would ask Dr Kissinger to carry on and there is no reason to expect the Secretary of State will refuse. But he must waste no time in cleaning out the White House staff.