Traci Mumford

signed on to a series of updated treaties.

The most recent was under Obama in 2010.

That was called the New START Treaty.

Mr. President, just one more thing.

But as of today, it has expired.

And so for the first time since 1972, the U.S.

and Russia have no limits on the size of their arsenals.

Many experts agree with what the Trump administration has argued, that the treaty was in need of updates.

It needed to cover more types of weapons, and more countries needed to sign on, etc.

But the complete absence of an arms control agreement comes at the very moment world leaders are considering expanding their capabilities.

Russia has done test launches to prepare for nuclear weapons in space and a test of an underwater drone that could detonate a warhead and trigger a radioactive tsunami.

China now has the world's fastest-growing nuclear arsenal, trying to rival Moscow and Washington.

And Japan, South Korea and Turkey, which are non-nuclear countries, are now discussing whether they need to change course.

Some countries in Europe are wondering the same, feeling like they can no longer rely on the U.S.

for protection and might need their own weapons.

Analysts say this all leaves the Trump administration with a choice.

It can push ahead with its own larger arsenal and specialized weapons to keep pace, or it can try and negotiate a new deal.

That would require Trump pushing on Moscow, though, and it would require China to engage on the topic, which it has so far refused to do.

For now, two of the U.S.

's leading nuclear experts have warned that, quote, "...nuclear weapons are back with a vengeance."