Los Angeles is expected to be the epicenter of toay’s nationwide “Day Without Immigrants” protests and rallies. Local officials have said they are bracing for a turnout perhaps larger than the mega-rally of March 25, which brought a half-million pro-immigrant demonstrators into downtown Los Angeles.

Similar demos and rallies are planned Monday for some sixty cities. And in many of them–as in Los Angeles–there’s an active internal debate over which tactics should predominate. Organized labor, the Catholic church and some of the leading immigrant advocate groups in LA have argued to ignore and eschew calls for an economic boycott and a school walk-out, claiming they might be politically alienating at a time when public opinion is shifting in favor of immigrants. These groups have organized their own after-work rally to compete with the pro-boycott events scheduled for midday and organized by smaller groups.

The internal movement debate, however, seems likely to be blurred and overridden by sheer numbers. The call for a May 1 action seems to have struck a nerve and, according to various reports, there are many employers (including major meatpacking and poultry companies) who will be voluntarily closing their doors for the day.

Any way you cut it, we seem to be amid a rapidly building and historic social movement whose scope and contours seem impossible to anticipate. Keep tuned here from an on-the-scene report from colleague Jon Wiener.