Nearly two dozen demonstrators arrested last year while protesting the New York Police Department's stop-and-frisk policy have gone on trial.

Some 22 people arrested in October outside a Harlem police station appeared in court Monday. Two accepted offers to get their cases dismissed by staying out of trouble for six months.

The group on trial includes Princeton University professor and civil rights activist Cornel West. It's one of the biggest groups to go to trial together over political protest arrests in New York City in recent years.

In her opening statement, Manhattan Assistant District Attorney Michelle Bayer said the protestors “intended” to be arrested. Prosecutors said they blocked the entrance to the precinct, formed a human barricade on the sidewalk and ignored orders to leave.

Defense lawyers have said there's reasonable doubt that any laws were broken. During several hours on Monday, Detective Michael Beatty took the stand about a video he had recorded of the protest. Under cross-examination by defense lawyers, Beatty admitted he never recorded nor saw any of the 20 defendants actually blocking access to the police station. The lawyers also took pains to point out that pedestrians could have passed by on the sidewalk, which they say would not have been possible if protesters were truly blocking off the area. 

Judge Robert Mandelbaum on Monday barred the defense from making another argument: that the protestors' conduct was justified. Mandelbaum said for a justification defense to work, the defendants would have to prove their actions were necessary to avert imminent harm or an immediate emergency. He pointed out a class action suit against the NYPD’s stop-and-frisk practices was currently pending in court.

The protestors are using the trial to spotlight their concerns about the NYPD’s stop-and-frisk polices, charging the department with using a tactic that disproportionately impacts people of color.

The police have long denied they racially profile individuals they stop and frisk and have defended the practice as an important way to combat violent crime.

Disorderly conduct is not a crime – it’s a violation. If convicted, the protestors could face up to 15 years in jail.