A national network of progressive groups began a grass-roots effort this week to help President Obama wage his fiscal fight with Congress.

The goal is to pressure key lawmakers in both parties whose votes could be critical to any debt-reduction deal, and it comes as Obama begins making his sales pitch to the public with a trip Friday to Pennsylvania.

The push by the progressive groups began Thursday with rallies outside the offices of five Republican House members in Florida. On Saturday, hundreds of similar events will unfold nationwide in a “national day of action” intended to influence negotiations on a series of automatic spending cuts and tax increases set to take effect Jan. 1.

Some lawmakers will even be greeted with revelers singing politically themed Christmas carols in the coming weeks, organizers said.

The emerging campaign, involving dozens of national and state-level organizations, will allow thousands of field organizers and volunteers from Obama’s 2012 reelection campaign to continue working on his behalf. At a time when the future of Obama’s campaign committee — and its precious e-mail lists and voter data files — are being decided, the outside groups are trying to replicate the president’s grass-roots success.

“We can’t do that as a campaign — it’s illegal,” said a senior Obama campaign adviser who spoke on the condition of anonymity, referring to lobbying on Washington legislation. “And we’re not going to just set up another entity without thinking about it. There's a great group of progressives working on it, and it’s a perfect place for our volunteers to be engaged for the month.”

The progressive groups are working in tandem with Obama, who will travel to Hatfield, Pa., on Friday to make the case that tax rates should be increased for the wealthiest 2 percent of Americans. But there remains ample room for friction between the White House and progressives on the issue of entitlement spending, which Obama has said is in need of reform but which many of his liberal allies want kept off the negotiating table.

There is also potential for tension between the White House and centrist Democratic senators, who will be among the lawmakers whom some liberals plan to target. In the early years of Obama’s first term, several Capitol Hill Democrats bristled when his grass-roots campaign organization — which by then had been moved to the Democratic National Committee — focused on them in an effort to win votes for the Affordable Care Act.

It’s not clear whether the White House will be better insulated this time, because independent groups are doing the targeting.

“This is all about shoring up our champions, making sure our champions are leading on the issue,” said Frank Clemente, who leads Americans for Tax Fairness, a labor-funded group. “This was a decisive issue in the election, and they need to stay strong on this.”

Leading the effort is a coalition of liberal groups called the Action, which pledges on its Web site “to end the Bush tax cuts for the richest two percent.” The coalition is staging rallies this weekend in at least 15 states.

One reason for the focus on tax cuts rather than spending cuts is broad public consensus on the issue. According to a new Washington Post-ABC News poll, raising taxes on income over $250,000 remains a popular approach to dealing with the country’s budget woes.

“We just went through an election cycle where a clear message came out of it,” said Christian Ulvert, a Miami-based organizer for the Action. “Tax cuts for middle-class families are the priority, and they cannot be held hostage to allow the debate to take place around whether the Bush tax cuts expire on the top 2 percent.”

The left is more divided on how to trim federal programs. Some groups adamantly oppose any cuts to Social Security, Medicare or Medicaid while other liberal organizations say some program cuts will be necessary to attract support from House Republicans.

Michael Morrill, the executive director of Pennsylvania-based Keystone Progress, said his group is urging both an end to the tax break for the wealthy as well as a hands-off policy when it comes to Social Security. But regarding entitlement programs more generally, Morrill said some level of compromise will be necessary.

“The Democrats do not have the majority, and even when they do have the majority, there is not an ideological purity within the Democratic Party,” Morrill said, referring to Republican control of the House. “There’s going to be stuff in whatever final deal comes down that I don’t like and that Keystone Progress as an organization doesn’t like.”

Morrill said activists in Pennsylvania will canvass neighborhoods and stage vigils in five moderate and independent-leaning House districts held by Republicans, including Rep. Charlie Dent, a Republican from Allentown. The group will stage a 30-hour vigil outside Dent’s home, a symbol of the 30 days remaining before the deadline to reach a deal.

“These are not places where a solidly tea party-type position is going to have a lot of sway,” Morrill said. “Members in those districts are going to have to be more flexible.”

Tea party activists also are beginning to regroup in the post-election era. FreedomWorks, a Washington-based conservative group that played a huge role in organizing the tea party in 2009 and 2010, will host a “fly-in” this weekend with more than 100 activists from around the country meeting in Washington to take stock of the election results and plan for the months ahead.

The Action and its partners are playing a role that some liberal activists had expected Obama’s campaign operation to assume. Four years ago, his campaign committee was reformed as an arm of the DNC, but officials said it is too soon to know what shape it will take this time.

As they did in 2008, Obama operatives surveyed supporters this month asking what they’d like to see happen to the committee. About 80 percent said they want to continue volunteering on behalf of the president’s policy agenda.

“We want to get input from folks who made up the organization and see what they want to do,” said Mitch Stewart, who coordinated the Obama campaign’s strategy in the battleground states. “That will be the foundation for the decision. We want to keep the organization going and support the president’s agenda.”