Washington (CNN) The U.S. government on Monday found itself with fewer tools to investigate terrorism -- at least temporarily -- after the Senate let provisions of the Patriot Act expire Sunday night.

While officials warned of national security risks, it is clear that the lapse will not come close to debilitating counterterrorism efforts.

The Senate entered a debate period late Sunday on the Patriot Act that pushed beyond the midnight deadline, effectively ending three provisions of that law, including the National Security Agency's bulk data collection program.

The lapse was a huge victory for privacy hawks who have called for changes to that program and others under the Patriot Act since Edward Snowden first blew the lid off the NSA's domestic surveillance programs in 2013.

The National Security Agency officially shut down the bulk metadata collection program officially at 7:44 p.m. Sunday night, a senior government official told CNN. Officials had previously indicated they would shut the program down around 8 p.m. to ensure all procedures were in place before midnight military time.

The Senate is expected to restore the expiring authorities midweek, but here's what we know will change between now and then:

What counterterrorism tools does the U.S. lose?

The government loses authorities under three Patriot Act provisions.

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The biggest and most controversial is the government's sweeping powers under Section 215 that allow the NSA to collect telephone metadata on millions of Americans and store that data for five years. That is, for the time being, gone.

Law enforcement officials also won't be allowed to get a roving wiretap to track terror suspects who frequently change communications devices, like phones. Instead, they will need to get individual warrants for each new device.

And third, the government loses a legal provision allowing it to use national security tools against "lone wolf" terror suspects if officials can't find a connection to a foreign terror group such as ISIS, for example. But that provision has never been used, the Justice Department confirmed.

The House overwhelmingly passed a bill, the USA Freedom Act, that would make big changes to the first, but leave the latter two provisions intact.

That bill would have the telephone companies hold Americans' telephone metadata and require the government to get a specific warrant to seize any telephone metadata -- and not on millions of people, but instead on specific individuals.

So those tools are now completely gone?

Not exactly.

FBI and NSA officials are allowed to continue using Section 215 and the roving wiretap provision in investigations they began before the June 1 expiration date.

Any new investigations will have to go without the roving wiretaps and the ability to petition the secret FISA court for warrants to seize business records, like telephone metadata, in terrorism cases. That court was established under the Foreign Intelligence Surveillance Act to provide warrants in national security cases.

The NSA's bulk metadata collection program was actually slated to end at 8 p.m. ET Sunday to ensure the government is in compliance with the deadline by midnight in military time as well.

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The process of winding down that program was ongoing last week, and the NSA was slated to cut off its connections to telecommunications companies starting at 4 p.m. ET Sunday.

Why is it such a long process?

Officials said the government began "winding down" the bulk data collection program during the week leading up to the deadline.

A U.S. administration official who spoke to CNN on the condition of anonymity to discuss sensitive information said "taking down the system" involves shutting off inputs between telecom companies and U.S. intelligence, "bringing down servers" and configuring "our monitoring software" to keep officials from accessing any data at telecommunication companies.

"We lock the system down so that there is no chance that data comes or data could be accessed during that time frame," the official said.

And the Department of Justice spent last week communicating the potential changes to its authority to collect data to telecommunications companies, according to a Justice Department official and a telecommunications company official familiar with the process.

"Really it's about just letting them know that on midnight on the 31st, they're not going to be able to provide the legal documents and the warrant and we're not going to give them anything," the telecommunications company official said.

The Justice Department official pointed to "legal and technical processes that need to occur" for the program to shut down.

So could America be less safe?

Attorney General Loretta Lynch said last week the United States would face a "serious lapse" in national security.

Director of National Intelligence James Clapper said in a statement on Friday the United States "would lose entirely an important capability that helps us identify potential U.S. based associates of foreign terrorists."

But opponents aren't convinced. Instead, they're determined not to let fears over national security trump civil liberties and privacy concerns.

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The American Civil Liberties Union said Thursday that "efforts to short-circuit reform efforts should not be allowed to succeed."

"Allowing the provisions of the Patriot Act to sunset wouldn't affect the government's ability to conduct targeted investigations or combat terrorism," the ACLU said. "The government has numerous other tools, including administrative and grand jury subpoenas, which would enable it to gather necessary information."

What are the facts on the expiring capabilities?

As it stands, several official review boards -- including a presidential review group and a government privacy oversight board -- found that the bulk metadata collection program was not essential to thwarting a single terror plot.

The Obama administration endorses the plan under the USA Freedom Act to transform that program.

The roving wiretaps provision that can be used in terrorism cases is used less than 100 times per year, but officials could be in a bind when it comes to new investigations.

Authorities could still obtain standard wiretaps on a suspected terrorists' phone, but a new phone requires a new warrant.

Justice Department spokesman Marc Raimondi said the top-secret nature of the investigations make even that a challenge.

"When we're chasing a terrorist or a spy, almost everything we have is highly, highly classified. Normal courts are not set up to handle that," he said.

Photos: Notable leakers and whistle-blowers Photos: Notable leakers and whistle-blowers Former intelligence worker Edward Snowden revealed himself as the source of documents outlining a massive effort by the NSA to track cell phone calls and monitor the e-mail and Internet traffic of virtually all Americans. He says he just wanted the public to know what the government was doing. "Even if you're not doing anything wrong, you're being watched and recorded," he said. Snowden has been granted temporary asylum in Russia after initially fleeing to Hong Kong. He has been charged with three felony counts, including violations of the U.S. Espionage Act, over the leaks. Hide Caption 1 of 15 Photos: Notable leakers and whistle-blowers Military analyst Daniel Ellsberg leaked the 7,000-page Pentagon Papers in 1971. The top-secret documents revealed that senior American leaders, including three presidents, knew the Vietnam War was an unwinnable, tragic quagmire. Further, they showed that the government had lied to Congress and the public about the progress of the war. Ellsberg surrendered to authorities and was charged as a spy. During his trial, the court learned that President Richard Nixon's administration had embarked on a campaign to discredit Ellsberg, illegally wiretapping him and breaking into his psychiatrist's office. All charges against him were dropped. Since then he has lived a relatively quiet life as a respected author and lecturer. Hide Caption 2 of 15 Photos: Notable leakers and whistle-blowers Starting in 1932, the U.S. Public Health Service studied untreated syphilis in black men who thought they were getting free health care. The patients weren't told of their affliction or sufficiently treated. Peter Buxtun, who worked for the Public Health Service, relayed information about the Tuskegee syphilis experiment to a reporter in 1972, which halted the 40-year study. His testimony at congressional hearings led to an overhaul of the Health, Education and Welfare rules concerning work with human subjects. A class-action lawsuit was settled out-of-court for $10 million, with the U.S. government promising free medical care to survivors and their families. Here, participants talk with a study coordinator. Hide Caption 3 of 15 Photos: Notable leakers and whistle-blowers In 2005, retired deputy FBI director Mark Felt revealed himself to be the whistle-blower "Deep Throat" in the Watergate scandal. He anonymously assisted Washington Post reporters Carl Bernstein and Bob Woodward with many of their stories about the Nixon administration's cover-up after the June 1972 break-in at the Democratic National Committee headquarters. The stories sparked a congressional investigation that eventually led to President Nixon's resignation in 1974. The Post won a Pulitzer Prize for its coverage. Felt was convicted on unrelated conspiracy charges in 1980 and eventually pardoned by President Ronald Reagan before slipping into obscurity for the next quarter-century. He died in 2008 at age 95. Hide Caption 4 of 15 Photos: Notable leakers and whistle-blowers Mordechai Vanunu , who worked as a technician at Israel's nuclear research facility, leaked information to a British newspaper and led nuclear arms analysts to conclude that Israel possessed a stockpile of nuclear weapons. Israel has neither confirmed nor denied its weapons program. An Israeli court convicted Vanunu in 1986 after Israeli intelligence agents captured him in Italy. He was sentenced to 18 years in prison. Since his release in 2004, he has been arrested on a number of occasions for violating terms of his parole. Hide Caption 5 of 15 Photos: Notable leakers and whistle-blowers President Ronald Reagan addresses the media in 1987, months after the disclosure of the Iran-Contra affair . A secret operation carried out by an American military officer used proceeds from weapons sales to Iran to fund the anti-communist Contras in Nicaragua and attempted to secure the release of U.S. hostages held by Iran-backed Hezbollah in Lebanon. Mehdi Hashemi, an officer of Iran's Islamic Revolutionary Guards Corps, leaked evidence of the deal to a Lebanese newspaper in 1986. Reagan's closest aides maintain he did not fully know, and only reluctantly came to accept, the circumstances of the operation. Hide Caption 6 of 15 Photos: Notable leakers and whistle-blowers Tobacco industry executive Jeffrey Wigand issued a memo to his company in 1992 about his concerns regarding tobacco additives. He was fired in March 1993 and subsequently contacted by "60 Minutes" and persuaded to tell his story on CBS. He claimed that Brown & Williamson knowingly used additives that were carcinogenic and addictive and spent millions covering it up. He also testified in a landmark case in Mississippi that resulted in a $246 billion settlement from the tobacco industry. Wigand has received public recognition for his actions and continues to crusade against Big Tobacco. He was portrayed by Russell Crowe in the 1999 film " The Insider ." Hide Caption 7 of 15 Photos: Notable leakers and whistle-blowers For 10 years, Frederic Whitehurst complained mostly in vain about practices at the FBI's world-renowned crime lab, where he worked. His efforts eventually led to a 1997 investigation that found lab agents produced inaccurate and scientifically flawed testimony in major cases, including the Oklahoma City and World Trade Center bombings. The Justice Department recommended major reforms but also criticized Whitehurst for "overstated and incendiary" allegations. He also faced disciplinary action for refusing to cooperate with an investigation into how some of his allegations were leaked to a magazine. After a yearlong paid suspension he left the bureau in 1998 with a settlement worth more than $1.16 million. Hide Caption 8 of 15 Photos: Notable leakers and whistle-blowers FBI whistle-blower Coleen Rowley accused the bureau of hindering efforts to investigate a suspected terrorist that could have disrupted plans for the September 11, 2001, terror attacks. In 2002 she fired off a 13-page letter to FBI Director Robert Mueller and flew to Washington to hand-deliver copies to two members of the Senate Intelligence Committee and meet with committee staffers. The letter accused the bureau of deliberately undermining requests to look into Zacarias Moussaoui , the only person convicted in the United States of playing a role in the attacks. She testified in front of Congress and the 9/11 Commission about the FBI's mishandling of information. Rowley was selected as one of Time magazine's People of the Year in 2002 , along with whistle-blowers Sherron Watkins of Enron and Cynthia Cooper of WorldCom. Hide Caption 9 of 15 Photos: Notable leakers and whistle-blowers Sherron Watkins, a former vice president at Enron, sent an anonymous letter to founder Kenneth Lay in 2001 warning him the company had accounting irregularities. The memo eventually reached the public and she later testified before Congress about her concerns and the company's wrongdoings. More than 4,000 Enron employees lost their jobs, and many also lost their life savings, when the energy giant declared bankruptcy in 2001. Investors lost billions of dollars. An investigation in 2002 found that Enron executives reaped millions of dollars from off-the-books partnerships and violated basic rules of accounting and ethics. Many were sentenced to prison for their roles in the Enron scandal Hide Caption 10 of 15 Photos: Notable leakers and whistle-blowers Cynthia Cooper and her team of auditors uncovered massive fraud at WorldCom in 2002. They found that the long-distance telephone provider had used $3.8 billion in questionable accounting entries to inflate earnings over the past five quarters. By the end of 2003, the total fraud was estimated to be $11 billion. The company filed for bankruptcy protection and five executives ended up in prison. Cooper started her own consulting firm and told her story in the book "Extraordinary Circumstances: The Journey of a Corporate Whistleblower." Hide Caption 11 of 15 Photos: Notable leakers and whistle-blowers In 2003, federal air marshal Robert MacLean anonymously tipped off an MSNBC reporter that because of budget concerns, the TSA was temporarily suspending missions that would require marshals to stay in hotels just days after they were briefed about a new "potential plot" to hijack U.S. airliners. The news caused an immediate uproar on Capitol Hill and the TSA retreated, withdrawing the scheduling cuts before they went into effect. MacLean was later investigated and fired for the unauthorized disclosure of "sensitive security information." Hide Caption 12 of 15 Photos: Notable leakers and whistle-blowers Joe Darby is the whistle-blower behind the Abu Ghraib prison abuse scandal in Iraq. He says he asked Army Reserve Spc. Charles Graner Jr. for photos from their travels so he could share them with family. Instead, he was given photos of prisoner abuse. Darby eventually alerted the U.S. military command, triggering an investigation and global outrage when the scandal came to light in 2004. Graner was sentenced to 10 years in prison for his part in the abuse. He was released in 2011 after serving 6½ years of his sentence. The military and members of Darby's own family ostracized him, calling him a traitor. Eventually he and his wife had to enter protective custody. Hide Caption 13 of 15 Photos: Notable leakers and whistle-blowers The New York Times reported in 2005 that in the months after the September 11, 2001, attacks, President George W. Bush authorized the U.S. National Security Agency to eavesdrop without a court warrant on people in the United States, including American citizens, suspected of communicating with al Qaeda members overseas. The Bush administration staunchly defended the controversial surveillance program. Russ Tice, an NSA insider, came forward as one of the anonymous sources used by the Times. He said he was concerned about alleged abuses and a lack of oversight. Here, President Bush participates in a conversation about the Patriot Act in Buffalo, New York, in April 2004. Hide Caption 14 of 15 Photos: Notable leakers and whistle-blowers Army Pfc. Bradley Manning was convicted July 30 of stealing and disseminating 750,000 pages of classified documents and videos to WikiLeaks, and the counts against him included violations of the Espionage Act. He was found guilty of 20 of the 22 charges but acquitted of the most serious charge -- aiding the enemy. Manning is set to speak in his defense when he takes the stand during the sentencing phase of his court-martial on Wednesday, August 14. He could face up to 90 years in prison if the judge imposes the maximum sentence. Hide Caption 15 of 15

Officials say the rising threat of lone wolves -- including those inspired by ISIS, but not ordered -- raises the need to maintain that provision of the Patriot Act.

But they concede the provision had not been used, even as the FBI has increasingly focused its efforts on lone wolves.