The operational effect may be limited because the surveillance laws remain in effect for existing investigations.
As we explained earlier, of the three provisions in question,
(1) the “business records” provision;
(2) the “roving wiretap” provision; and
(3) the “lone wolf” amendment to the FISA definition of “agent of a foreign power”.
only #1, regarding "business records" was really controversial. This was the provision that allowed NSA to scoop up all metadata. Later developments led to the FBI grossly abuse their ability to search NSA databases in order to try to prevent Donald Trump's election--and when that failed to lead an Intel Community coup against the president.
Even this temporary lapse of these provisions is unlikely to have much effect, as the NYT explains:
Still, the lapse of several more weeks may not have a significant operational effect on the F.B.I., said Julian Sanchez, a specialist in surveillance legal policy at the Cato Institute.
That is because of the way the law is written. A so-called savings clause permits the laws to remain in effect for investigations that already existed on March 15, or for new investigations into events that occurred before then.
“The authorities remain available for either investigations open at the time of expiration or investigations predicated on underlying conduct that predates the sunset date,” Mr. Sanchez said.
The F.B.I. has open-ended investigations into long-term organizational threats, including major terrorist groups like Al Qaeda and the Islamic State and the espionage agencies of foreign adversaries like Russia and China. Thus, the FISA court that has oversight of national security surveillance can still issue orders giving investigators the power to target a newly identified suspect linked to one of those entities.
A majority of lawmakers in both chambers support extending the expired provisions, but they have been caught up in a larger argument over whether and how strictly to impose new restrictions on the F.B.I.’s FISA powers after an inspector general’s damning report found numerous factual errors and omissions in applications to target the former Trump adviser Carter Page during the Russia investigation.
The House passed a bill, ... that would extend the expiring provisions while making changes to FISA.
The House bill, for example, would push the FISA court to appoint an outsider to critique the government’s arguments when a wiretap application raised serious issues about First Amendment activity, which could include political campaigns.
It would also make clear that the government cannot use a FISA business records order to collect information — like cellphone location data, which in a criminal investigation requires a search warrant — that has a higher legal standard.
But amid objections from libertarian-leaning senators of both parties that the House bill fell short in curtailing surveillance powers, the Senate did not take it up.
Instead, the Senate voted to temporarily reinstate the three tools unchanged until June — giving itself more time to negotiate its own surveillance overhaul package. But the House did not cooperate.