WASHINGTON (AP) — Demonstrators upset over the election of Donald Trump have marched in cities around the country over the past week, and some are making plans to be in Washington for his inauguration Jan. 20. But whether marches will become a movement is an open question.

At this early stage, the protesters who have taken to the streets to brand Trump a bigot and a sexist and chant "Not my president!" appear to be mostly venting their frustrations and do not seem to have coalesced behind overall leaders or a common set of demands.

Columbia University professor Todd Gitlin, who as an early leader of Students for a Democratic Society helped organize an anti-Vietnam War demonstration that brought thousands to Washington in 1965, said the anti-Trump protests by themselves "are not the makings of a movement."

"A movement requires that clusters of people take responsibility for creating vehicles that can carry through, focus energy, develop priorities, strategize, recruit, figure out how to govern themselves," Gitlin said.

For that to happen, a critical mass of protesters has to "transform their mindset from protest into successful politics, which is much less exciting," he said. Gitlin said that means "dirtying our hands in winning local and state battles which are instrumental to changing the national balance."

On Monday, hundreds of students decrying Trump's election walked out of schools in Denver, Los Angeles and Silver Spring, Maryland, after a weekend in which thousands of people demonstrated around the country and scores were arrested. Protesters threw rocks at police in Indianapolis and hurled bottles and other objects in Portland, Oregon. Marchers have also converged on Trump Tower in New York, the president-elect's transition headquarters.

Among other things, the demonstrators have condemned Trump's behavior toward women and his stand on immigration and civil liberties.

Ralph Young, a history professor at Temple University in Philadelphia who teaches a course on dissent in America and has written two books on the topic, said it is too early to predict what the marches might become.

Once Trump becomes president and starts making policy decisions, that could crystalize opposition and focus people's attention on certain issues, he said. If the anti-Trump demonstrations are going to become a movement, they also need leaders who can articulate their grievances, he said.

That's one thing the Occupy Wall Street movement against economic inequality never really achieved — a proper organization, Young said.

Jamie Henn of the group 350, which organizes protests to fight climate change, said liberal activist groups are still scrambling to figure out how they will push back against a Trump presidency.

"There is definitely stuff coming together and being planned that looks like the messy process of everyone and their mother throwing up something on their Facebook page," Henn said.

Henn said liberals haven't seen the need for this level of mobilization since the run-up to the Iraq War. But activists remember glumly how little a dent their big marches against the invasion made then, and may use different tactics this time.

Some groups are already trying to come together, though there are differences of opinion, said Greg McKelvey, a protest organizer in Portland, Oregon. McKelvey said demonstrators are trying to organize with counterparts in New York; Washington; Austin, Texas; Oakland, California; Boston; and a few other cities.

Some activists want to prevent Trump somehow from becoming president, while others feel that's inevitable and instead want to insulate their communities from his policies, McKelvey said. He said his group, Portland's Resistance, aims to make sure city and state governments are working on issues such as limiting climate change, pushing for better health care and dealing with racial disparities in policing.

Trump's election has made activists out of people who haven't been part of any organized demonstrations before.

Olivia Antezana, a 19-year-old sophomore at the University of Maryland at College Park, had never been to a demonstration before creating and promoting a "Not My President" event on Facebook. By Monday afternoon, 18,000 people had indicated on Facebook that they would be going to the event in Washington on Inauguration Day.

"I will say I certainly underestimated it," Antezana said.

Still, Antezana said she is not sure what she will do after the demonstration she is planning is over. She doesn't plan to join a political campaign, she said, though she would like to keep up with activism. Right now, she said, she has another priority: school.

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Associated Press writers Sarah Brumfield in Washington; Nicholas Riccardi in Denver; and Andrew Selsky in Portland, Oregon, contributed to this report.

Follow Jessica Gresko on Twitter at https://twitter.com/jessicagresko.