With Russia in mind, the Trump administration is aiming to develop new nuclear firepower that it says will make it easier to deter threats to European allies.
That plan isn't yet approved by President Donald Trump. It's intended to make nuclear conflict less likely. Critics argue it would do the opposite.
The proposal is spelled out in a policy document that puts the U.S. in a generally more aggressive nuclear stance.
It's the first such review since 2010 and is among several studies of security strategy undertaken since Trump took office.
In many ways it reaffirms the nuclear policy of President Barack Obama, including his commitment to replace all key elements of the nuclear arsenal with new, more modern weapons over the coming two decades.
