By Jonathan Beale
BBC News, Washington
When President George W Bush first met Russia's President Vladimir Putin five years ago in Slovenia, he suggested he had found a kindred spirit.
Mr Bush once saw eye-to-eye with Mr Putin - but no longer
The US president said at the time: "I looked the man in the eye. I was able to get a sense of his soul."
He praised Mr Putin as a man deeply committed to his country.
The American president may now be regretting those remarks. Certainly it has brought criticism from both the right and the left.
The hawkish Republican Richard Perle has said: "When you gaze into souls, it's something you should update periodically, because souls can change."
John Edwards - the former Democratic vice-presidential candidate - says the remarks did "great damage" to America and its relationship with Russia because the White House was then too slow to recognise Moscow's move away from democracy.
Mr Edwards has accused Mr Bush of being much too soft on Mr Putin.
The president now has plenty of reasons to reconsider his relationship with Russia's leader.
Condoleezza Rice has been critical of Russia's leaders
The US administration worries about a power grab by the Kremlin.
Secretary of State Condoleezza Rice has voiced strong concerns about curbs on the media and NGOs, Russia's respect for the rule of law and the direction of democratic reform.
Vice-President Dick Cheney has been even more blunt.
He has accused "opponents of reform" of seeking to reverse the gains of the last decade.
In a speech in Vilnius he gave in May, which provoked anger in Moscow, Mr Cheney also charged Russia with using its energy supplies to blackmail and bully other nations.
The US is also worried about Russia's wider influence around the globe - such as Moscow's willingness to sell weapons to Venezuela.
The rhetoric out of Washington may be a reminder that these are the two old enemies of the Cold War.
The US hopes Russia can help show the way out of the Iran crisis
But times have changed. America now needs Russia's help more than ever.
Russia is a key player in multinational talks aimed at curbing both North Korea and Iran's nuclear ambitions.
Moscow has been reluctant to follow Washington's calls for the threat of punitive measures, but the US can not resolve these issues on its own.
With Russia central to US diplomatic efforts to resolve both crises, Mr Bush will choose his words with care when he meets Mr Putin.
In Germany en route to Russia, Mr Bush said: "Nobody really likes to be lectured a lot. And, therefore, if you want to be an effective person, what you don't do is scold the person publicly all the time."
His national security adviser, Stephen Hadley, said Mr Bush would raise concerns about Moscow's democratic backsliding "frankly, but privately".
So Mr Bush will be more careful with any criticism - but he'll also be more cautious with his praise.
There may be mutual respect - but Presidents Putin and Bush are far from being soulmates these days.