By William Horsley BBC European Affairs correspondent

The protests that have taken place in Berlin in advance of the arrival of US President George W Bush reflect the concern among many ordinary Germans about America's current political leadership.

Bush may have lost much of the goodwill shown to his father

But the demonstrations are part of a long tradition of political struggle in Berlin, the city which the US defended against the threat of communist takeover throughout the years of the Cold War.

German police, anxious to minimise any possible risk to the safety of the US president, have thrown up a strict security cordon around the centre of Berlin.

So the city which welcomed George Bush senior as a saviour after the fall of the Berlin Wall now appears to be protecting his son, also as president, from the hostility of tens of thousands of German people.

Active role

The main thrust of the protests - by the so-called Axis of Peace organisation - is against America's use of massive military power to achieve its goals in Afghanistan and its potential use in the future against Saddam Hussein's leadership in Iraq.

But opinion polls show that half the German population is openly critical of US leadership for a number of reasons:

• Its failure to consult its allies as promised
• Its refusal to sign up to joint action against global warming
• Its protectionist stance on trade issues such as steel and agriculture.

German leaders are trying to play down these differences, stressing Germany's active role in support of the US-led campaign against international terrorism.

But it is hard to avoid the conclusion that this American president has lost much of the goodwill that was shown to his father 13 years ago.

History of protest

Berliners have always been quick to protest.

Protesters are angered by Bush's failure to act on global warming

In the 1960s this was a headquarters of left-wing radicalism.

Former US President Richard Nixon's cortege was pelted with stones here at the height of the Vietnam War.

Ronald Reagan also faced mass protests as a Cold War warrior in 1987, on the same trip as when he famously stood in front of the Berlin Wall and called on Mikhail Gorbachev to tear it down.

Now George W Bush faces posters saying "Stop Bush's global war".

But as more sober commentators point out, what most of the protesters really want is evidence that the US president really is listening to his allies and that he will not misuse America's military dominance in areas of conflict.