Thousands of spectators’ green hats, shamrocks and cameras surrounded a traditional march down Market Street Saturday in the oldest and largest Saint Patrick’s Day parade west of the Mississippi.

Amidst the camera flashes and “Kiss me, I’m Irish” t-shirts, a subtext of protest and political disharmony wove through the event, revealing a more comprehensive presence of Irish culture and history.

The event began at 11:30 in the morning, with three horse-mounted policemen leading a slow charge from Market and Second streets with about 30 members of the Irish Pipers Band right behind, playing tunes like “The Wearing of the Green,” a traditional Irish protest song, on bagpipes and drums.

The parade continued all the way down to City Hall, and behind the band followed a long series of dancers, local government and union representatives, and flag wavers. The crowds took pictures while people on the floats tossed out candy. Mayor Gavin Newsom stood with several of the marchers for about 10 minutes, shaking hands and posing for photographs.

But at about the half-way mark, a more aggressive and iconoclastic kind of Irish culture marched.

“Britain kills Democracy in Ireland,” read a banner held by members of the Pearse and Connolly Fife and Drum Band, which named itself after the leaders of the Easter Rising of 1916 in Ireland.

“The British have reneged on their part of The Good Friday Agreement,” said Walter Finnerty, who marched with the band.

Passed by an overwhelming majority in 1998, the Good Friday Agreement was seen as a huge step forward in the Northern Ireland peace process and in establishing self-rule in Ireland. But the government it established was suspended in October 2002, when unionists, often seen as sympathetic and loyal to the British crown, alleged that the Irish Republican Army was engaged in spying, in violation of the agreement.

Northern Ireland has remained under direct British rule since.

“The IRA dis[armed],” per the terms of the Good Friday Agreement, Finnerty said. “And if the British keep reneging on their commitment to leave Ireland alone, you can put this down: there will be another IRA. Every generation of Ireland took up arms, and it will happen again.”

Further down the parade, The Irish Lobby for Immigration Reform marched with banners reading “legalizetheirish.org” and chanting the rights of Irish immigrants.

Their presence at the march came on the heels of a huge protest in Washington D.C. on March 7, when the ILIR brought 3,500 volunteers to the nation’s capital, pushing through a snowstorm to lobby Congress for immigration reform.

“We don’t want amnesty. We want a path to citizenship for the 50,000 Irish immigrants in this country, 4,000 of them right in this community,” said Jack Fitzpatrick of the Irish Immigration Pastoral Center. “They’re all paying taxes, and they deserve the rewards for what they bring to this country.”

Even the green hats and shamrocks spectators wore to the San Francisco parade had their place in Ireland’s historical struggles. In the late 1700’s, wearing a shamrock in one’s hat was a sign of rebellion against the government, and green was the official color of a republican revolutionary organization.

“It’s a sign of protest, the wearing of the green,” said Finnerty. “It used to be you could be hanged for it. You could be arrested just for possession of an Irish flag. So the IRA started putting them up on flagpoles with pipe bombs. The British army would try to take the flag down, and: boom! Of course, after a few soldiers were killed, they just started knocking over the poles.”

The parade ended about 2:00, and many attendees left the Civic Center area for another gathering on Townsend Street, which had been blocked off between 2nd and 3rd streets. Aside from a ten-minute performance from the Irish Pipers Band, the Townsend gathering had no entertainment and no music playing.