Did Boston Police Violate the First Amendment by Selectively Arresting Occupy Boston Protesters?

Earlier this week, the Boston Police arrested 141 members of the Occupy Boston movement who were protesting on a section of the Rose F. Kennedy Greenway.  Footage of the arrests can be seen here: http://www.youtube.com/watch?v=l6FfO2rRbeQ&feature=player_embedded

These protesters were charged with trespassing and unlawful assembly.  However, other protesters, mere yards away on a different section of the Greenway, known as Dewey Square, were allowed to protest without harassment or arrest.  Is such an arbitrary enforcement of the law evidence of selective enforcement, and therefore a violation of the protesters' First Amendment rights?

Selective enforcement is not always unconstitutional.  A certain amount of leeway is given to authorities, be it prosecutors or police officers, to enforce the law.  For example, a police officer at a speed trap need not ticket every driver she encounters going over the speed limit, but may use her discretion in ticketing only the most egregious speeders.  However, when discretion goes so far as to show the purposeful and intentional decision on behalf of the officer to enforce (or not enforce) the law because of an arbitrary or unjustifiable standard, then the officer's actions (or inactions) become unconstitutional.  Such arbitrary or unjustifiable standards include motivations based on race, gender, religion, national origin, and for purposes of inhibiting the First Amendment.

The 2nd Circuit has upheld this premise in the realm of freedom of expression cases.  In Dwares v. City of New York, 985 F.2d 94 (2nd Cir. 1993), police inaction was found to be unconstitutional when officers did nothing to stop the assault of a protester who was in the midst of burning the American flag.  Because the officers' inaction was the motivation of prohibiting free speech, their failure to stop the assault was considered unconstitutional.

Here, in regards to the Boston protesters, the facts are quite different.  Two groups of protesters within the same Occupy Boston movement were in the same public park (albeit different sections) and in violation of the same laws.  However, the police chose to arrest only one part of the protesters (the faction that was spreading to the next section of the Greenway), while the previously occupied section remained untouched.  In this instance, by arresting only a portion of the protesters, they are effectively limiting the spread of the protesters' message.  Using selective arrests in order to curtail the message of a protest group may not be considered a viewpoint-neutral enforcement of the law, and therefore may be unconstitutional.