The revelations that secretive government programs have been used to aggressively mine the communications of millions of Americans are forcing lawmakers on Capitol Hill to revisit some of the controversial intelligence surveillance laws that Congress has routinely approved and re-approved with little fanfare in recent years.

Nearly 50 lawmakers — senators and congressmen, Democrats and Republicans — expressed outright opposition or deep concern about reports that the National Security Agency has been operating a pair of programs that collect data on phone calls made by Americans and monitor communications by foreigners through records obtained from U.S. Internet companies.

Many of the skeptics are longtime opponents of the expanded powers Congress has granted intelligence agencies, but others had been supporters of the measures. And for nearly 200 senators and representatives — those elected in the recent wave elections — this marked their first brush with a heated debate that consumed Capitol Hill from 2005 until early 2008.

Taken together, the critical statements signaled that, nearly 12 years into the nation’s war against terror, there is growing concern about a permanent national security structure that has the ability to easily violate the privacy rights of U.S. citizens.

“If our government is going to become Big Brother like this, people need to know it and decide whether that’s what they want,” House Judiciary Committee Chairman Bob Goodlatte (R-Va.) said Friday on “The Laura Ingraham Show,” a syndicated radio program. The panel’s ranking Democrat, Rep. John Conyers Jr. of Michigan, normally a staunch Obama ally, said Friday that “serious alarm bells” went off when The Washington Post revealed Thursday that it has acquired documents showing the sweeping monitoring of U.S. companies such as Facebook and Google for e-mail and video communications by foreigners.

The issue splinters the normal ideological coalitions across the House and Senate, cobbling together a civil libertarian collection of conservatives and liberals who are also distrustful of too much government power.

The controversy also has created a political convergence among congressional leaders who have spent years fighting each other on other issues: House Speaker John A. Boehner (R-Ohio) and Senate Majority Leader Harry M. Reid (D-Nev.) lead the bipartisan defense of the aggressive surveillance techniques.

With the Senate expected to focus on immigration legislation for the rest of June, the next possible battleground for curtailing security methods would be in the House, where Majority Leader Eric Cantor (R-Va.) has informed colleagues that the annual intelligence authorization bill should come to the floor this month. The Pentagon policy bill also could come to the floor, setting up two possible venues for lawmakers trying to rein in the powers of the intelligence community.

Those efforts will likely face steep odds, given the bipartisan leadership support for the aggressive techniques, but the mere focus on the issue marks a significant change from the past five years of relative atrophy in terms of congressional oversight of the methods used to track potential terrorists.

The laws in question were adopted in the immediate aftermath of the Sept. 11, 2001, terrorist attacks, when Congress hurriedly passed the Patriot Act. Among other things, it loosened the rules on the government’s gathering of commercial records for investigations.

When Congress reauthorized the Patriot Act in 2006, the main opponents of some of the Bush White House’s approaches to combat terrorism were Democrats. Subsequent debates in 2007 and 2008 set the framework for the laws that are now in question.

The 2008 debate culminated with then-Sen. Barack Obama (D-Ill.) and then-House Speaker Nancy Pelosi (D-Calif.) supporting the law. In the Senate, every Republican supported tough surveillance methods; in the House, just one Republican opposed the tough new measure.

In the intervening years, a growing strain of libertarianism rose among conservative activists, headlined by the election of Sen. Rand Paul (R-Ky.) and a few dozen similarly minded House Republicans in 2010.

The first sign of trouble came in February 2011, when more than two dozen Republicans opposed an extension of three provisions of the Patriot Act. Parliamentary hurdles temporarily blocked reauthorization.

But Congress eventually approved extending those provisions, and in late December Congress gave a five-year extension to most provisions of the law governing the special court that oversees these cases, guided by the Foreign Intelligence Surveillance Act. The Senate considered just three amendments, offered by Paul and two other longtime opponents of the spying techniques, Oregon Sens. Ron Wyden and Jeff Merkley, both Democrats. The amendments were defeated and the measure approved with 73 votes in a debate that barely spanned a full day.

At the time, most of Congress was preoccupied with the tax-and-budget debate over “the fiscal cliff.”

Paul elevated attention on civil liberty issues with a 13-hour filibuster of CIA Director John Brennan’s nomination this spring, but that focused on the agency’s use of drones to attack alleged terrorists in tribal areas of Pakistan, Afghanistan and Yemen.

When news broke of the NSA’s sweeping collection of telephone data by millions of Americans, the House GOP’s newcomers led the charge in questioning its constitutionality.

Nearly two dozen House members — largely Republicans first elected in 2010 or 2012 — sent a letter to Brennan and FBI Director Robert S. Mueller III expressing their “significant concerns” about the issue.

On Friday, Obama challenged his critics, noting that every member of Congress was made aware of one of the programs in question, while senior leaders and top lawmakers on the intelligence committees were briefed on the other.

On Thursday, Boehner avoided criticizing the programs and instead said Obama needed to provide explanations about how the programs stopped terror attacks.

“It’s important for the president to outline to the American people why the tools that he has available to him are critical to the threats that we may — that we may have,” Boehner told reporters.