After nearly a week of intense, behind-the-scenes wrangling, congressional negotiators late Tuesday agreed to include in the pending Sept. 11 security bill sweeping liability protections for citizens who report suspicious activity they fear might be linked to terrorism.

The provision is meant to address the so-called "Flying Imams" case, wherein six Muslim clerics sued passengers aboard a Northwest flight in March who reported them to authorities, leading to their detention. The clerics were cleared but their lawsuit, many lawmakers feared, would discourage future vigilance among the flying public.

• Get complete coverage in FOXNews.com's War on Terror Center.

The Sept. 11 bill is a top Democratic priority and Republicans fought hard to include the passenger immunity protection, creating common cause with Connecticut Independent Joe Lieberman, chairman of the conference committee knitting together the House and Senate bills designed to implement unfulfilled security recommendations of the Sept. 11 commission.

The bill was expected to swiftly pass the House and Senate and be signed into law by President Bush.

House Democrats, led by Mississippi's Bennie Thompson, sought changes in the immunity language but ultimately were overwhelmed by the Lieberman-GOP coalition on the conference committee.

A joint statement on the inclusion of the John Doe Protections language for terrorism tipsters by House Republican Leader John Boehner, R-Ohio, and ranking member of the Committee on Homeland Security Peter King, R-N.Y., follows.

"This is a huge win — a hard-fought victory for House Republicans and, more importantly, for the American people," King said.

"In a post-9/11 reality, vigilance is essential to security. Despite the Democratic opposition to this important homeland security measure, I’m thrilled to announce that common sense has prevailed and heroic Americans who report suspicious activity will be protected from frivolous lawsuits. The American people were heard and our country is safer because of it."

Added Boehner: "I’m pleased that Democratic leaders finally decided to do the right thing and agreed with Republicans that we should be encouraging Americans to report potential terrorist activity to the proper authorities."

"This much-needed measure is critical in the effort to confront the significant threats posed by Al Qaeda and other terrorists and protect the American people. I want to thank Reps. King and [New Mexico Republican Steve] Pearce for their leadership on this issue and their efforts to make America safer."