Both Barack Obama and I are Chicago boys, schooled in the tough-minded, arm-twisting don't-mess-with-me attitude of crushing rather than compromising with your unforgiving enemies. We are both products of machine politics, I from the west side's "rotten borough" 24th ward loyally turning out Democratic party majorities of almost, and sometimes exceeding, 100% ("Vote early, vote often!"), and Barack from a south side community-organising operation that got things done door-to-door, block by block.

In the 2008 election campaign President Obama's most important strategist was the Chicago fixer David Axelrod, a master of hard-knuckle progressive neighbourhood politics who had masterminded the re-election campaign of Chicago's first African American mayor Harold Washington. But after Obama's inauguration the new president appears to have muzzled Axelrod in favour of Rahm Emanuel, a ferociously combative, rightwing Democratic political assassin. The enforcer Emanuel has so far failed to enforce much of anything for Obama by way of decent legislation, and Axelrod is sidelined except as a mouthpiece.

No wonder that at home on my desk is a manila folder file labelled OBAMA BETRAYALS OF CAMPAIGN PLEDGES, so full it's bursting apart. I was about to start a fresh new file of his latest missteps when suddenly I caught myself. Hey, wait a minute, I'm falling into the same old tired habit of reflexive negativity honed in the Bush years.

Howard Zinn, the historian-activist who before his recent death was probably the wisest mind on the US left, told us he was not disappointed in Obama because he never expected much in the absence of a national movement to push him in a good direction. Zinn – a lifelong student of the American abolitionist, labour, civil rights, feminist and gay rights movements – preached that real change "will have to work its way from the bottom up". Alas, we at the "bottom" have not really been there for Obama to fight for his ear, which currently belongs to Wall Street.

Franklin Roosevelt, the president we hoped that Obama would be like, had a huge advantage over our new president. At FDR's disposal were powerful mass movements – Huey Long's "Share the Wealth", Father Coughlin's radical racist anti-capitalist broadcasts, the elderly Townsend Clubs, the veterans' bonus marchers and militant labour unions with their sit-down strikes – that were an effective threat, a countervailing force to rich rightwingers eager to destroy the New Deal. FDR's good angel, his wife Eleanor, constantly reported to him about just how bad it was in the real world of the Great Depression. But Roosevelt told Eleanor and anyone else who came to him with demands for progressive change: "OK, you've convinced me. Now go out and put pressure on me."

That's where we've let Obama down. We on the American left – in a dysfunctional marriage with a bought-and-paid-for Democratic party, tamed by leechlike dependence on "non-profit" liberal foundations themselves funded by corporations, a women's movement obsessed by the abortion issue, a gay movement fixed on gay marriage – simply aren't up to the job. We have not backed up Obama with a serious antiwar movement (there isn't any), and our Big Labour is too weak to fight for itself, let alone for the rest of us. Grassroots activism still exists, but during the 2008 presidential campaign we slipped into the habit of allowing ourselves to be used purely as fundraising vehicles. Fundraising is no substitute for hell raising, as the Palin-loving Tea Baggers and Town Hallers are teaching us.

Obama came into office with a mandate for change. That should have been our signal not to sit back and wait for him to deliver but to mobilise to make sure he followed through. Instead, we relaxed our "Chicago muscle", the hard volunteer work that elected him. And I started my self-satisfying, ultimately pointless OBAMA BETRAYAL file.

Last week in America's northwest, Oregon voters, who are traditionally anti-tax-increase, showed how Chicago muscle works. Against fierce opposition led by Nike and other big businesses, they delivered a huge progressive victory by approving tax-raising measures on the wealthy and corporations. They did it the low-tech way, slogging door to door, volunteers from an improvised coalition of unions, community groups and small businesses, working together to overcome a well-funded rightwing scare campaign.

Sooner or later we on the American left will rise again and look beyond single-issue obsessions, sever our dependence on corporate charity, and – as FDR and Howard Zinn advised – relearn the lesson of how to apply pressure on a president who needs us more than we need him.