CNN
We are getting things started with START.
It stands for Strategic Arms Reduction Treaty.
It's an agreement between the United States and Russia
for both countries to reduce the number of nuclear weapons they have.
President Obama also says it's part of the effort
to "reset" the relationship between the two countries.
Yesterday, he and Russian President Dmitry Medvedev
got together in the Czech Republic
to sign off on START.
The agreement cuts the number of nuclear weapons
that the U.S. and Russia have by about a third.
The White House is scheduled to hold a meeting
on nuclear security next week.
It's something that President Obama says
affects the entire world.