This is false. The reason there's no US troops in Iraq today is that the democratically elected Iraqi government wouldn't agree to a status of forces agreement with us. Status of forces agreements are pretty standard, the US has agreements with every country that we have troops in, especially our allies like Germany and Japan. The Iraqi government decided they didn't want to agree to a SOFA, so we left. If the Iraqi government were our puppets, we would have pressured them into agreeing to the SOFA.
Sounds naive. US left Iraq because no powerful US corporation was interested enough in staying. Probably because there is not much to gain there anymore. Or because Iraq government is controlled well enough without military presence. The goal is not a military presence, the goal is to get rich. Military is just a tool.
That's different. bin Laden was hiding out in Afghanistan and launched terrorist attacks against the United States. The Taliban was supporting him, both before and after the 9/11 attacks. If you go around committing acts of war, you can expect a military response.
In other views the reason to invade Afghanistan was Afghanistan Oil Pipeline (http://en.wikipedia.org/wiki/Afghanistan_Oil_Pipeline).
OTOH, can fact that country doesn't extradite a criminal be a reason for invasion? What's next: invading Ecuador for Assange and Russia for Snowden?
Actually, the United States was in Vietnam at the request of the South Vietnamese government, who wanted our help repelling the North Vietnamese army, who had invaded South Vietnam in violation of a UN order. So yes, the US was asked to intervene in Vietnam.
Democratically elected president of Ukraine Viktor Yanukovych use asked Russia to use force in Ukraine (not in exact this words, but fairly close), after he had to flee Ukraine. People of Crimea have had a referendum and by vast majority decided to join Russian Federation. The whole 'annex' thing happened without shots and with much celebration in Crimea. So yes, Russia was very much asked to come to Crimea.
US (and EU), on the other hand, openly supports and funds people who using force overthrown democratically elected government in Ukraine - and those people have never been elected. Clear invasion in Ukraine's internal business. Just like Iraq - we will tell you whom you can democratically choose from.
I'm not defending Putin's actions. I'm just saying that US is as bad and is leading by example. And overall it's not that people are bad, it's the structure of life, law of the nature.