Those unions by themselves are capable of turning out a pretty sizable march. We obviously know that Occupy Wall Street has that ability. Then add in "MoveOn.org and community organizations like the Working Families Party and United NY," the Chinatown Tenants Union, many more unions and community organizations, and likely students from local colleges, and, well, this really could be something else.
It's important to recognize, though, that however many extra bodies show up today, the reason the media is paying attention is because of the sustained occupation. We know the media is comfortable ignoring thousands or tens of thousands of progressives protesting for a day; we've seen it again and again. Today, though, will put together ongoing disruption and a mass of people, and it's not going to be ignored.
One big question is whether today's march will once again involve mass arrests, as happened Saturday. Arrested Occupy Wall Street protesters from Saturday have filed a civil rights complaint against the city:
"After escorting and leading a group of demonstrators and others well out onto the Brooklyn Bridge roadway, the NYPD suddenly and without warning curtailed further forward movement, blocked the ability of persons to leave the bridge from the rear, and arrested hundreds of protesters in the absence of probable cause," they said in the complaint.
The protesters, whose demonstration continued yesterday with as many as 1,000 people in Lower Manhattan, seek a declaration nullifying the arrests, that police violated the U.S. Constitution and an order barring the city from using similar tactics in the future. The group also seeks unspecified damages.
Whatever the ultimate fate of that lawsuit, the Transport Workers Union was unsuccessful in its attempt to get a judge to block police from forcing bus drivers to transport arrested protesters. The question is, will there be arrests that make that likely to happen again?
[Judge] Engelmayer disagreed with [TWU attorney] Schwartz's argument that police may commandeer buses again during a march planned for today, saying that assessment is "highly speculative" and that the police are likely to be more prepared than they were last weekend.
"Last Saturday involved very unusual circumstances," Arthur Larkin, an attorney with the city's Law Department, said in a statement. "The court appropriately found that the police department's limited use of MTA buses was not unreasonable."
Note that the judge and the city attorney aren't saying they don't expect mass arrests—just that if there are, the police will be better prepared and probably won't be commandeering MTA buses. But with all the established, legal-department-having groups involved in today's protest, expect serious legal fireworks if there are questionable arrests.
Today's march is at 4:30 PM ET. It starts at Foley Square, near but not right at City Hall.