Sadly, I don't exactly have enough time now to list all the possible reasons in detail along with explanations, but I'll give you a few things to think over. (The movie linked to earlier has a few possible, if indirect, reasons)
In a reasonable world, none of these reasons alone would warrant what had happened; even all of them put together should not warrant what had happened, if it indeed was anything else than a tragic plane crash. But I'm not quite sure whether this world is reasonable in the normal sense of that word.
The thing many people fail to see is that it was not just Lech Kaczyński, there were many other important people there (unfortunately). And when there is such a big jackpot to be won, the question is no longer "why?", but "why not?", I'm afraid.
Hopefully, I'll have a bit more time soon and I'll try to put together what has been established thus far, here is a short resume of the most prominent pieces of the puzzle.
Lech Kaczyński:
[*] His Eastern/Central Europe policy: rapprochement with Ukraine and helping Ukraine come closer to EU, rather than Russia (think gas pipelines going through Ukraine; gas price hikes Moscow retaliated with; Russian Crimean naval bases); spotlighting the Russian-Georgian war to international public opinion (also think of the Georgia/Ukraine alternative route for pipelines — an alternative to the Russia/Germany
Nordstream pipeline AND the support for Georgia in NATO idea); working towards creating a block of Poland/Ukraine/Georgia/Latvia with aspirations towards widening that block; insistence on full disclosure of Katyń files.
[*] Objections to the Poland-Russia gas deal, in which not only would Poland pay a premium on that gas, compared to what it paid earlier, but it would be buying more than previously which increased the share of foreign gas used in relation to Polish gas. This was highly controversial, especially in the light of -
[*] Alleged rich shale gas deposits, which Kaczyński was interested in expoliting to decrease energy dependence from Russia
[*] Knowledge of the contents of the final report from the liquidation of WSI (a military intelligence service in which there was never a serious move to remove former communist agents), and his accedence to the liquidation in the first place
Sławomir Skrzypek (chief of NBP, the national bank):
[*] Intended not to renew the flexible crediting line from IMF, which was not being used anyway (monetary deposits had increased during Skrzypek's tenure). The crediting line was renewed in June 2010.
The Generals:
[*] Liquidation of WSI
[*] their presence in NATO structures, their experience and knowledge (esp. Franciszek Gągor)
Janusz Kurtyka, chief of IPN (national remembrance institute):
[*] emphasis on the independence of the IPN from the cabinet
[*] publication of documents questioning facts from the communist period. For instance, something that's been around since 1992 (when PM's Oleszewski was dismissed from office overnight, when he intended to publish the names of people who've worked with SB, the secret police, during communist times; this was done thanks to, among others, Donald Tusk and the then president Lech Wałęsa, who wanted to prevent becoming known as an associate of the SB) was that a book detailing Lech Wałęsa's contacts with the SB was published (yes, he was the same guy who was one of the leaders of Solidarity; the same guy who's been awarded with the Nobel Peace Prize).
Now this all rests on the assumption that former communist agents are still around and have influence within the governing structures.
But you have to remember that unlike, for instance, Romania, former communist leaders were not killed. They were made deals with. Fair enough, that's civilised.
Until you hear about the "serial suiciders", deaths and accident.
[*] Grzegorz Michniewicz, general director of PM Tusk's office. Hanged himself on Wednesday 23rd Dec 2009, which was the day the TU-154m returned from a general renovation in Samara, Russia.
[*] Krzysztof Knyż, a cameraman for (the pro-government-ish) private TVN. This one's iffy, but some people claim he'd been in Smoleńsk on the 10th Apr 2010, and later died (in Moscow?) on Monday, 31st May 2010. All this may be just allegations, but the truth is that whenever an employee of TVN died, there was always a mention of him in their news program, along with the cause of death. Knyż didn't get a mention. (He was 39.)
[*] Prof. Marek Dulinicz, archeologist, he was supposed to head the group of archeologists meant to go to Smoleńsk and search for body fragments, fuselage fragments, anything. He died in a car accident, on Sunday 6th Jun 2010, shortly before leaving to Smoleńsk. In the end, no archeologists were sent.
[*] Dariusz Szpineta, pilot, flight instructor. He questioned the official reports concerning the crash several times. He was found dead in a bathroom in a hotel room in India, on Friday 2nd Dec 2011.
[*] Gen. Sławomir Petelicki, first head of GROM (the special forces unit), former intelligence officer. He criticised the findings of the Committee for Investigation of National Aviation Accidents and the government's clumsiness in explaining the disaster. He allegedly shot himself in the underground parking lot of his block of flats, in an area that was out of sight of CCTV. This happened on Saturday, 16th June 2012.
[*] Col. Leszek Tobiasz, former WSI officer. In Nov 2007 he was the man who went to then newly-chosen Marshal of the Parliament Bronisław Komorowski (current president), Paweł Graś (then chief of the parliamentary commission overseeing intelligence services; spokesperson for PM Tusk since Feb 2009) and gen. Krzysztof Bondaryk (chief of ABW, internal security agency). He informed them of possible corruption in the verification committe of WSI, allowing people to bribe their way into SKW (military counter-intelligence; it was the direct descendant to WSI).
Tobiasz was 55, he fell over while dancing and died on a ball on (Friday 17th Feb 2012?). He was to testify in the corruption case on 1st March 2012.
[*] The Samoobrona people (Self-defence). You may have heard of Andrzej Lepper (a funny bit of trivia is that whenever BBC wrote of him, to my knowledge, is that they always described him as "a volatile pig-farmer"). His party, along with Liga Polskich Rodzin (Leage of Polish Families, a right-wing catholic party) was part of the ruling coalition with Prawo i Sprawiedliwość (Law and Justice, led by Lech Kaczyński's twin brother, Jarosław) from May 2006. The coalition fell apart after sex scandals and, more importantly, the so-called "afera gruntowa" (land scadal). Jarosław Kaczyński then dismantled the coalition on 16th November 2007, and dismissed his cabinet. An early election was called and won by Donald Tusk, who then formed his 1st cabinet (and PiS no longer held both the Presidential and PM posts; in the wake of the air crash, PO, the Civic Platform, hold both the Presidential and PM posts).
But let's get back to the Samoobrona people and their deaths:
- Ryszard Kuciński, Andrzej Lepper's lawyer. He died on (Thursday 26th May 2011?) in one of the hospitals in Warsaw.
- Wiesław Podg