Shades of Ron Brown's (Commerce Secretary under Clinton) last plane ride. Certain folks in Russia would have had plenty of reasons to cut off the head of Poland's government.
President Kaczyński was one of few our politicians who didn't wanted too many compromises with Russia. There was a tendency of not taking him seriously, as he had a harsh tongue for a politician and was generally considered a bit paranoid. But he actually was one of the few in Europe who actively opposed to Russian involvement in 2008 Georgia/Osetia conflict and was trying to reveal the tracks that the conflict might have been secretly escalated by Russia in the first place.
In our country people tend to know well how Russia government uses the policy of hiding or denying the facts. They used it when tsars ruled, then again during the communism, and again these times. Regardless of what really happened during today's crash, they will make obstacles to investigate it while pretending to be helpful.
Don't get me wrong, I know and like many Russian folks in person, but still their government is one of the crappiest (and most dangerous), by the standards of western democracies.
http://www.alertnet.org/thenews/newsdesk/LDE63A08I.htm
Fortunately!!
What, Poland would declare war on Russia? I have my doubts.