The US, Russia and "Hybrid Warfare" After years of counterinsurgency in the Middle East, the Pentagon says the biggest threat to US security is Russia. That's not just because of Russia's nuclear weapons, it's "hybrid warfare" of the sort Vladimir Putin is using in Eastern Ukraine. US troops are already training to combine counterinsurgency with conventional weapons, street-level fighting, cyber-warfare and propaganda. One very concrete example of that changing strategy took place in the Mojave Desert earlier this month in an exercise called Operation Dragon Spear. The goal is deterring Russia from moving on NATO members Latvia, Estonia and Lithuania -- or other members of the former Soviet Union.

Is Vladimir Putin Changing the Game in Ukraine? Yesterday, as bloody violence continued to increase in Ukrainian cities, Germany's foreign minister warned that the country was on the "threshold of war." Britain's foreign secretary said Russia was creating a pretext for military intervention. Today, Vladimir Putin stunned diplomats by announcing a troop pull-back from the Ukrainian border and voicing support for upcoming elections. The Pentagon sees no evidence of troop movements yet, but Russia's President may have undercut Western accusations that he's trying to scuttle Ukraine's democracy. We hear from Moscow and Ukraine. Will European observers assist a transition from confrontation to dialogue? Has Putin's announcement demonstrated how completely he's in control?  What's the lesson for the Obama Administration and superpower politics?

At the Economic Summit, Syria Takes Center Stage Presidents Obama and Putin shook hands as Obama arrived in Russia for the G20 summit today, but that's apparently as close as they're going to get. Russia's grant of asylum to Edward Snowden, the leaker of American secrets, has dramatized the increasing gulf between the two countries. Obama says he's decided on military action in Syria, while Putin's opposed , while neither side has gone public with the evidence needed to make its case. Whatever happened to Obama's "reset" of relations with Russia?  Are the differences between the two countries irreconcilable? Will Obama gain the backing of other nations while he's in Russia? Should he have stayed home to persuade Congress and the American people?

Resurgent Russia, Friend or Foe? The US may not want to resume the Cold War, but Vladimir Putin's Russia shows signs of returning to Soviet-style authoritarianism. The Kremlin is taking over powerful industries and the media. Political critics, business rivals and reporters have been murdered in mysterious circumstances. In Munich this weekend, Putin used an international forum to berate the US for destabilizing the world by ignoring international law. Defense Secretary Robert Gates and the Bush Administration are playing it down, but what does Putin's aggressiveness mean--at home and abroad?  We get perspective from journalists and Russia experts, including the attorney for Mikhail Khodorkovsky , the former head of Yukos Oil , who is serving time in a Siberian prison for fraud and tax evasion.