Russia

Russia is a stagnate nation with not much going for it except some oil.  Putin is using it for his glory.  (Compare to China which is growing in power because of the rise of the people with the Communist Party stumbling to control it.)  No one has ever complained of US manufacturing or technical jobs being outsourced to Russia.  Unfortunately, they do have some moderately usable military weapons and a collection of nuclear arms which may or may not blow up where they are expected to.  Either way, it's enough to make us hold back a bit. 

In that context, Putin is trying to gain power and expand the Russian empire for his personal glory.  A side effect of his glory is that of his military and people.  If he can knock off a couple easy victories like annexing Crimea and helping Assad wipe out half the population of Syria, he can brag to his people.  Of course, those people will want more and bigger victories.  Therein lies a problem.  Russia does not have economic or cultural connections with its neighbors to worry about destroying.  Appeasing Putin will work as well as the last time appeasement was tried. 

Putin will continue to interfere with the Middle East and may want to try his hand in Eastern Europe.  To the Middle East, let him.  Maybe he'll invade Afghanistan again.  See if it works out any better this time.  Let the terrorist set their sites on Russia.

Eastern Europe is a bit more tricky.  Estonia, Latvia, and Lithuania are in NATO.  If Belarus and Ukraine joined NATO as has been pursued, the US would have 1,500 miles of border, some of which is 300 miles from Moscow, to station troops on.  That would be the equivalent of Russia posting troops, missiles, equipment, and airplanes on the Canadian border from Maine to Minnesota.  It's not hard to play off fears when your 70-year enemy is stationing troops 300 miles away.  Eastern European countries will be better off with economic, political, and cultural ties to Europe and the US rather than with Russia.   However, building those ties will be an affront to Russia regardless of who is in power. 

Russia is a declining state.  It did not invest in any education or technical infrastructure during the heyday of oil prices.  It produces nothing of significant value to the world.  (It sells a few cars to Kazakhstan.)  They can hack some soft targets like someone's barely secured e-mail.  (95% of the operating systems in Russia are made in America.  The chips are Intel and AMD based.  Do they really want to start a cyber-war?)  They are dangerous and could cause a great deal of damage if provoked and/or mismanaged.  We probably need an agreement on how to handle the five European countries bordering Russia.