It was almost as if the ghosts of the 1960s anti-war movement had risen and returned to the doorstep of the White House. Families with small children, ageing hippies, war veterans and widows clapping and dancing in time to Native American drums, and the occasional waft of marijuana smoke.
'It's great to see kids at this demo - but I think there's more apathy now than during Vietnam,' said Gina Mahern, 54. Despite having to catch a 4pm flight to Chicago, she was determined to make it to the White House. It was already 2pm.
'Bush is definitely much more unpopular than [former president Richard] Nixon ever was, that's for sure,' she said as the procession slowly meandered up the street.
One banner in a sea of thousands at the rally read: 'This is what democracy looks like.' Others read 'Worst President Ever' and 'Yee-Haa is Not a Foreign Policy'.
Paul Abernathy served in Iraq for a year, from the opening assault in March 2003. 'I believe very strongly against the war in Iraq,' he said. 'I crossed the battle lines on the first day of the Iraq war - I didn't once believe we were there for the reasons we said we were. It's illegal and it's immoral.'
But as if to prove the day's democratic credentials, there were two sides to the rally. As the self-proclaimed sons and daughters of the civil rights movement trundled through the drizzle towards the navy memorial at the end of their route, they met their opposition.
'You should be ashamed of yourselves,' shouted John MacGuire, wearing a T-shirt depicting former president Ronald Reagan as Cuban revolutionary Che Guevara.
A group waving placards of anti-war campaigner Cindy Sheehan approached him, only to be stopped by a police line. 'You people are a joke,' he said, holding aloft his own banner, reading: 'They are not peace protesters. They are cowards and traitors - Fighting the left. Doing it right'.
He later explained his stance. 'We're here to show that not everybody is drinking the Kool Aid that the Michael Moores of this world are offering,' he said, mocking the liberals with a reference to the 1978 mass suicide of the People's Temple Cult.
'I am a US Marine Corps veteran, I was in the second battalion of marines during [Operation] Desert Storm in 1991 and I recognise that conflict is a terrible thing. But these people - they're not really anti war.
'Where was the war outrage when [former president Bill] Clinton sent us to the Balkans? Where was the war outrage when [he] sent us to Somalia? They say no to war unless a Democrat is president.'
Hayley Ganncoll, 22 - who had travelled from Nevada - agreed.
'My brother is in Iraq and I want him to know that not everyone believes that this is a terrible mistake. He's making a real sacrifice for something he believes in, and I think freedom is worth it. Freedom isn't free,' she said.
'I want my brother to be back home more than anything in the world, but we have to honour the sacrifices made by past and future veterans by fighting for freedom today.'
However, not all veterans saw it that way. 'I survived Vietnam,' shouted war veteran Mike Senior above the din. 'And you know what? I never thought I'd miss Richard Nixon. But the sheer idiocy of President Bush has made this possible. He needs to go.'