Good evening. I'm Jeff Bennett.

I'm the Navas is away.

On the news hour tonight, the expiration of a nuclear arms treaty between the U.S. and Russia

makes the future even more uncertain for the world's two largest nuclear arsenals.

Federal agents' use of surveillance tools to track immigrants and protesters

raises questions about civil liberties. And we look at the influence of presidential advisor

Stephen Miller on Trump administration policies and how he rose to his position of prominence.

Cultural issues can kind of catapult someone like Stephen Miller from the fringes to the

center of a conversation that's dominating the nation. Welcome to the News Hour.

For the first time in more than a half century, there are no limits on the world's two largest atomic arsenals.

The sole remaining nuclear arms treaty in the world, known as New Start, is expiring.

And arms control advocates fear a new arms race.

Nick Schifrin starts our coverage.

They're the world's deadliest weapons, able to obliterate entire cities.

And when mounted on missiles, can fly thousands of miles in minutes.

And for the last 15 years, the deployment of Russian and American long-range nuclear weapons

has been restricted.

Today is an important milestone for nuclear security and nonproliferation.

It was 2010 when President Barack Obama and then Russian President Dmitri Medvedev

signed the new Strategic Arms Reduction Treaty.

It limited the U.S. and Russia to 700 deployed intercontinental ballistic missiles on land,

at sea, and on heavy bombers.

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