Last nuclear treaty between US and Russia nears expiration as Trump and Putin trade testing threats

US President Donald Trump and Russian President Vladimir Putin have spent weeks trading threats to restart nuclear tests, an escalation kicked off by Putin’s boasts about tests of the Poseidon nuclear powered missile in late October.

​ US President Donald Trump and Russian President Vladimir Putin have spent weeks trading threats to restart nuclear tests, an escalation kicked off by Putin’s boasts about tests of the Poseidon nuclear powered missile in late October. Read More Breaking News, Latest News and Videos | CNN