Earlier quoted context omitted.
> Don't terms like "probable" and "my hypothesis" pretty obviously make this a statement of opinion, and therefore immune to libel claims? Quite possibly. But who wants to spend the legal fees to test that? Pragmatically, it's better to stay reasonably far away from the edge of that particular cliff, lest one be propelled over the edge by a random gust of wind (or a well-placed push).
I don't think that's a healthy attitude, especially when we're talking about the possibility of corruption. If we all take that "pragmatic" view, what will actually prevent corruption?
Journalists. They know that you avoid libel by stating facts supported by evidence. Truth is a defense to a libel charge (at least in the U.S.). And as mentioned above, when the libel plaintiff is a "public figure," a higher standard applies, precisely because of the public interest in ferreting out corruption and the like.