Mass urban protests have always been a necessary part of American democracy, giving people who are marginalized a voice and a way to exert influence they wouldn't otherwise have.

We've been seeing more of them in recent years because more people justifiably feel excluded from consideration when decisions that affect their lives are made.

Americans revere the Boston Tea Party, yet many see contemporary protest movements as irritants that exist outside the political process.

Large-scale protests don't happen unless there's a major problem, so rather than seeing them as annoyances, people should ask what's broken.

When low-wage workers walk out across the country, or when violence by police in New York and Ferguson, sparks protests as far away as Seattle, all of us need to listen.

People endlessly debate the details of particular wage plans or the sequence of events in Ferguson or even the character of Michael Brown, the young man shot dead by a police officer there, rather than looking up to see the larger reasons for protest.

Last week, I saw a play at the Seattle Repertory Theatre, Robert Schenkkan's "All The Way," about Lyndon Johnson and the civil-rights movement. The play was set in the 1960s but felt contemporary, as it dealt with the interaction between the federal government and a mass protest movement by people shut out of that power - an interaction that yielded improvements in our democracy that would not have happened without pressure from outside the political and economic establishment.

How much say do you feel you have when government and corporations are making decisions on issues you care about? Ordinary people are told to take their concerns to the voting booth. I make a point of voting, but at the same time I know election outcomes are shaped by elites and interest groups.

The National Rifle Association usually wins in Congress regardless of what opinion polls say voters want. Stadiums get built whether voters want them or not. Corporations demand and get special treatment all the time. The U.S. Supreme Court's Citizens United ruling even gave them supercitizen status, allowing them and other big players to spend on politics without restraint.

That's not good for democracy, and it is especially bad because enormous income and wealth inequality already distorts public life.

Martin Gilens of Princeton and Benjamin Page of Northwestern University wrote a paper that looked at voter- and interest-group positions on nearly 2,000 issues between 1981 and 2002 to see whose positions were reflected in policy decisions.

The study published this September in "Perspectives on Politics," a peer-reviewed journal of the American Political Science Association, concluded, "Multivariate analysis indicates that economic elites and organized groups representing business interests have substantial independent impacts on U.S. government policy, while average citizens and mass-based interest groups have little or no independent influence." What do you do if your positions are ignored? Well, nothing most of the time, but when the usual process causes real, ongoing pain, people can and do take to the streets.

The Stonewall riots, after a 1969 police raid on the Stonewall Inn, a gay bar in New York City, birthed a powerful rights movement for sexual minorities. Labor rights and women's rights have been advanced by civil disobedience.

Corporations can disrupt communities in significant ways, shutting down businesses, for instance, but they do it legally because they help decide what's legal.

Protests are a legitimate response by people who aren't being heard. They are often a last resort that can be disruptive and threatening. Even when most participants are peaceful, frustration and anger can turn some to violence. At other times, protests are polluted by people who use them as cover to break laws for personal reasons. In Ferguson, peaceful protesters were in the position of trying to ward off vandals and thieves. People watching protests unfold don't always make distinctions, but we should.

Not everyone who takes to the street has a just cause. But protests that reach the levels we are seeing now usually are saying something we need to hear.

Jerry Large is a columnist for The Seattle Times.