It seemed to be going so well. Chinese President Hu Jintao had arrived in the other Washington - State, not DC - happily adapting to his role as the leader of a new global power.
By Jonathan Beale
BBC News, Washington
Secret Service staff quickly moved to hush the protester
Even his reserve and awkwardness appeared to fade as he rubbed shoulders with the chairman and founder of Microsoft, Bill Gates. The world's new "big spender" with the world's richest man.
President Hu was warmly embraced by the staff of Boeing - buoyed by his promises to buy more of their planes. He even donned a baseball cap!
Was this a sign that these two great countries' mutual suspicions were melting away?
Even the White House had appeared to throw caution to the wind.
Okay, this was not the official state visit that the Chinese government had wanted, but when President Hu arrived in Washington DC he still received a 21-gun salute, a guard of honour and marching bands - all witnessed by every senior figure of the Bush administration.
But it then all unravelled. The Chinese may have been willing to overlook the foul-up as their National Anthem was introduced as that of "the Republic of China" - the other name for Taiwan - the part of China that has rebelled and broken away from the mainland and sought security from the United States.
But to have their president's speech interrupted by not just a protester, but one from the banned quasi-religious group Falun Gong, would have been difficult to swallow.
In Beijing, television screens showing the BBC and CNN went to black as the cameras focused on Wang Wenyi shouting out "President Hu, your days are numbered".
President Bush apologised to his Chinese guest for this unfortunate incident - but it showed the gulf that remains between these two countries.
The Falun Gong protester was only reflecting a wider disgust in Washington over China's human rights record.
And American concerns are not just confined to that one issue.
Republicans and Democrats are worried about the growing trade imbalance.
The Bush administration wants China to play a more active role in confronting the threat from Iran and North Korea's nuclear programme.
President Hu may in the end feel he got what he came for - a show of respect from the world's only superpower for the new kid on the block.
But discussions between the two leaders failed to produce anything concrete and the United States is still uncertain as to whether China will live up to its challenge of becoming a "responsible stakeholder" in the international community.
Relations may have improved - but there is still a lack of trust.
That one protester may have done everyone a favour by reminding us that China and America - whatever their common interests - are still poles apart.