On the corner of 14th and U Streets, ecstatic groups of people spilled out election parties and bars, chanting at each other across the traffic lights. Car horns blared and strangers exchanged high-fives. Then a man bearing a life size cut-out of Barack Obama aloft sprinted into the middle of the intersection and stood in front of traffic, dancing and waving as cars weaved and careered around him. A wave of humanity surged into the street after him - and the celebration party was on.

But for the entire evening beforehand it had been tense. In bar after bar decorated with red-white-blue rosettes, young Washingtonians sipped election-themed cocktails (the Donkey Punch, the Basil Barack Berry, the Pomegramitt Romney) and watched election coverage on flat screen TVs.

As in 2008, hope was the main emotion - but this time it was coloured painfully with anxiety. The talking heads conjured up graphics showing Florida, Ohio, Pennsylvania were "too close to call" while President Obama and Mitt Romney traded slim leads consisting of mere handfuls of votes. Asked if she thought Obama could retain the presidency, one young woman sitting at the bar at Policy, a laid back restaurant and watering hole, paused for a telling moment before replying, "Yes, of course... Yes we can!" A couple of young African-American women at a fashionable restaurant said they hoped Obama would be returned but they were worried.

At a party on R Street, a clutch of Democratic volunteers wearing Obama-Biden shirts were strangely subdued, texting friends and checking tweets and Facebook as they watched Rachel Maddow.

At 11pm, it happened. MSNBC called the election for the president as the numbers for Ohio firmed up. The streets echoed to screams of joy. And then the networks fell like dominos. Almost immediately even Fox News had called it for Obama, followed in due course by CNN and the BBC. The screaming got even louder. "Four more years! Four more years!" they chanted.

In the middle of the street, the man with the Obama cut-out swooped and jigged, the cardboard president smiling and bobbing in the air. People swirled around him - "O-ba-ma! O-ba-ma! O-ba-ma!" - and honking cars inched round the crowd. For chaotic minutes, the roads were filled with cars, bikes, dogs, people all milling about, before police arrived to block off the road and started trying to organise traffic.

Cameramen and TV reporters appeared on the scene and were promptly mobbed. Now hope was replaced by joy - and mixed with flooding relief.

"Oh my God, I was so stressed," one young woman said. "I was SO stressed for him!"

A circle formed as a man in an Obama shirt knelt in the street and asked his girlfriend to marry him. Weeping, she said yes. The crowd cheered even more. "This is amazing," one man said. "This is a one in a lifetime moment."

He lifted his arms to the chilly night sky and called out with all his strength: "Four more years!"