Grass-roots advocacy groups will kick off a national lobbying campaign later this week to rally support for a constitutional amendment that they hope will mute a recent Supreme Court decision.

People for the American Way, Public Citizen and other nonprofit organizations on Thursday will formally launch a new lobbying push to encourage Members — and ultimately state legislatures — to pass legislation that would reverse the Supreme Court’s Jan. 21 decision. In its 5-4 ruling in Citizens United v. Federal Election Commission, the high court’s conservative majority concluded that corporations share many of the same First Amendment protections as individuals when it comes to participating in federal elections.

Craig Holman, a Public Citizen lobbyist, said Thursday’s event will begin what is expected to be a very long process. In the meantime, his group is supporting other legislation in response to the decision, including shareholder protection proposals and a public financing system for Members.

“We need to now begin the dialogue with the greater community to start agreeing upon the language and agreeing upon the strategy to pursue this constitutional amendment,” Holman said of Thursday’s meeting among the groups. “We obviously have to make this national drive, but we will begin right here by solidifying enough energy in Congress to get this going.”

Holman said amending the Constitution is “a tough hill to climb.” According to the National Archives’ Web site, a constitutional amendment must first be approved by the House and Senate. After passage in both chambers, the proposal is sent to all 50 state legislatures. If 38 states agree — no small feat — the Constitution is changed.

The new coalition on Tuesday received the support of Senate Foreign Relations Chairman John Kerry (D-Mass.), who said he backs changing the Constitution “to make it clear once and for all that corporations do not have the same free speech rights as individuals.”

“The Supreme Court has issued a decision inflating the speech rights of large, faceless corporations to the same level of hard-working, everyday Americans,” Kerry said at a Rules and Administration Committee hearing Tuesday.

At the hearing, Kerry and other Senators heard from Fred Wertheimer, president of Democracy 21, who criticized the Citizens United decision. Steve Hoersting of the Center for Competitive Politics, however, told Senators that he supported the court’s ruling.

Kerry, though, continued his strong words for the Supreme Court. “The court has struck at the very heart of our democracy, a democracy in which corporations already have too much influence,” he said.

In the House, Judiciary Chairman John Conyers (D-Mich.) and Rep. Donna Edwards (D-Md.) introduced language for a constitutional amendment.

On her Web site, Edwards said the legislation will “address the flawed ruling by the Supreme Court allowing corporations to spend unlimited amounts of money on elections. … The amendment will undo the Supreme Court decision and allow Congress and the states to regulate the expenditure of funds by corporations for political speech.”

“The ruling reached by the Roberts’ Court overturned decades of legal precedent by allowing corporations unfettered spending in our political campaigns,” Edwards continued. “Another law will not rectify this disastrous decision. A Constitutional Amendment is necessary to undo what this Court has done. It is time we remove corporate influence from our policies and our politics. We cannot allow corporations to dominate our elections, to do so would be both undemocratic and unfair to ordinary citizens.”

The House Judiciary Committee and the House Administration Committee are holding hearings today on the Supreme Court’s recent decision.

Holman’s coalition will also include Voter Action, the Center for Corporate Policy and the American Independent Business Alliance. The coalition has started a Web site, freespeechforpeople.org, and is also using social networking tools such as Facebook and Twitter.

As of Tuesday, the group had about 270 Twitter followers and more than 5,000 Facebook members.

“Free speech rights are for people, not corporations,” John Bonifaz, legal director of Voter Action, said in a statement Tuesday. “Our history has included prior amendments to the US Constitution which were enacted to correct egregiously wrong decisions of the US Supreme Court directly impacting the democratic process.”

“The Court’s ruling in Citizens United v. FEC demands a similar constitutional amendment response,” he added.