It was quite a feat, given the packed House floor Monday night, the customary bear-hugging and jostling among other lawmakers. Then a doorkeeper sat the two politicians in the same row, only an aisle and four senators between them.
Sen. Edward M. Kennedy, D-Mass., was not caught in the middle. Earlier in the day, he had taken a side in the White House race, endorsing Obama. Kennedy was seated beside Obama, away from Clinton.
Nonetheless, Kennedy reached out to shake Clinton's hand when she came up the aisle. Clinton took Kennedy's hand. They shook. Obama had turned away.
A doorkeeper, caught in that highly awkward dance, cringes in the photo that captures the moment.
It was the latest chapter in the increasingly nasty fight between the two leading candidates for the Democratic presidential nomination.
Obama told reporters traveling with him Tuesday that he was surprised by the headlines and was simply responding to a question from a colleague when Clinton was near.
"Senator Clinton and I have had very cordial relations, off the floor and on the floor," Obama said. "I waved at her as I was coming into the Senate chamber before we walked over last night. I think that there's just a lot more tea-leaf reading going on here than I think people are suggesting."
Speaking Tuesday on Fox News, Clinton said: "I reached out my hand in friendship and unity and my hand is still reaching out. And I look forward to shaking his hand when I see him at the debate in California."
After the State of the Union address, Bush shook Obama's hand but not Clinton's.
The only Republican senator still running, John McCain of Arizona, wasn't there to shake any hands. He was busy doing that in Florida ahead of the state's primary.
