“The reason 2009 was so successful for the grass roots was because the politicians never saw it coming,” said Jennifer Stefano, the state director for the Pennsylvania chapter of Americans for Prosperity, a Tea Party group. “Now they know. And they are terrified.”

Many lawmakers, often from safe districts, are still holding town halls throughout the month. While a number of them are drawing voters outraged over Mr. Obama’s health care law, the intensity is nothing compared to the scale of 2009.

But where there are no gatherings, some groups have decided to take matters into their own hands.

After seeing a paltry schedule of Congressional town hall meetings this month, another major conservative group, Heritage Action for America, decided it would stage public forums of its own from Arkansas to Pennsylvania. The aim is to recruit people for a group it calls the Sentinels, a citizens’ brigade of sorts, to reach lawmakers through other means, like writing letters to the editor, dialing in to talk-radio programs and mastering the language of Twitter and Facebook.

The Democratic Congressional Campaign Committee is sending its advocates into Republican districts with two-dimensional cutouts of members without a traditional town hall on the calendar. Anyone who is feeling especially theatric is being encouraged to debate their cardboard congressman.

This month, the committee sent a batch of rubber ducks to Representative Rodney Davis, Republican of Illinois, who is under pressure to support a broad immigration overhaul. (The joke: He is “ducking” questions in an ethics investigation.)

Others on the Democrats’ target list have included Representative Tim Griffin of Arkansas, who was greeted at an airport by protesters calling for an end to the across-the-board budget cuts known as the sequester, and Representative John Kline of Minnesota, who is also being pressed to support immigration overhaul and was picketed after attending a closed-door Chamber of Commerce event. Not one of the Republican congressmen has a town hall scheduled this month.