KAREN GRIGSBY BATES, HOST:

The U.S. Senate is holding a rare Sunday night session this evening. Senators are facing a midnight deadline to extend surveillance powers for the nation's intelligence agencies. Otherwise, President Obama warns, national security could be at risk.

(SOUNDBITE OF PRESS CONFERENCE)

PRESIDENT BARACK OBAMA: I don't want us to be in a situation which, for certain period of time, those authorities go away, and suddenly, we're dark. And heaven forbid we've got a problem where we could have prevented a terrorist attack or apprehended someone who is engaged in dangerous activity, but we didn't do so simply because of inaction in the Senate.

BATES: Senators tried to pass a surveillance bill before they left home for the Memorial Day recess, but they came up three votes short of moving forward with the measure. So with the clock ticking, senators are back at it. NPR's Scott Horsley joins us now from the White House. Hi, Scott.

SCOTT HORSLEY, BYLINE: Hi, Karen.

BATES: The president's been pressing the Senate pretty hard, hasn't he?

HORSLEY: He really has. The White House has made a full-court press on this issue. You heard the president himself speaking at the Oval Office Friday. That was right after a meeting with his attorney general. The president also devoted his weekly radio address to this issue on Saturday. And the director of national intelligence has also weighed in. Everyone in the administration is urging the Senate to pass something called the USA Freedom Bill. That's a sort of compromise measure that was hammered out by law enforcement and civil liberties activists over the last year or so. And it's the rare bill that passed the deeply divided House of Representatives with truly broad and truly bipartisan support.

BATES: So, Scott, what's in that House bill?

HORSLEY: The House bill would overhaul the controversial collection of bulk telephone records. Remember, these were brought to light by Edward Snowden. The fact that the government's been hoovering up vast quantities of telephone metadata - that is the who called whom, when, for how long.

Under the House bill, the government collection of that data would be phased out over the next six months. And after that, it would be up to the phone companies to hold onto data, and the government could only look at it with a court order. Again, this is a compromise that has the backing of the White House and a lot of Republicans and Democrats in the House. And because of that broad support, no one on the House side really wants to reopen this issue. They're still on recess through tomorrow.

But some senators, including the majority leader, Mitch McConnell - he'd prefer to simply extend the existing bulk data collection. McConnell's Kentucky colleague Rand Paul has the opposite objection. Paul, of course, is running for president, and he wants to curtail surveillance even more. So there's been a real road block in the Senate, which the White House jokingly characterizes as another of Kentucky's historic feuds, up there with the Hatfields and McCoys, although Senators Paul and McConnell downplay that.

BATES: So, Scott, what happens if the Senate doesn't pass an extension tonight?

HORSLEY: Well, the government collection of metadata would stop. In fact, it's already begun shutting down. But in addition, several other surveillance powers would be suspended - powers that are not really controversial, but which are lumped into the same legislation and, therefore, sunset at the same time. That includes the government's authority to collect business records of suspected terrorists, the authority for something called a roving wiretap, which is useful for following a suspect who's constantly switching telephones, and another power which has never actually been used, but which is designed to let the government keep tabs on a suspected lone wolf. That is a potential terrorist who's not associated with a known terror organization. So those powers also lapse at midnight, unless the Senate finds a way out of this.

BATES: NPR's Scott Horsley. Scott, thanks so much.

HORSLEY: My pleasure, Karen. Transcript provided by NPR, Copyright NPR.