Yes. There are MANY oddities in the Oswald Odyssey. (Unintended...but
good...tongue twister.) I have little doubt that Marina could have, at
the very least, been a Soviet sleeper agent. However, no evidence beyond
the suspicions has ever come out that she actually was an agent or that
suggests she acted in that capacity even if should could have been
activated as a "sleeper."
Even if she was an agent and did act in that capacity, then what was her
purpose? If one suggests that it was to "move" LHO into position or one
day encourage him into being used as an assassin of a US President, it
would take some strong evidence to convince me. It just seems too
incredible that the Soviets would risk WWIII or retaliation on their own
leaders had Oswald (a known leftist) been traceable to a plot that
involved them.
I suppose they COULD have done it and somehow gotten away with it, but
it's hard to believe it could have been missed by the US Government
entirely given Oswald's status as a former Soviet defector. The only
scenario I see allowing that to happen very easily, would be with some
kind of complicity on the part of the US officials doing the
investigating. This could happen either by their active participation in
the plot to bump off Kennedy or by simply choosing to look the other way
to avoid WWIII.
The former seems far fetched even for a conspiracy theory. While I would
find the latter somewhat more understandable, I just can't see it being
successfully kept silent, nor can I imagine that the US Government could
have allowed their sworn enemy to get away "scott free" with such a brazen
attack. Even if publically acknowledging a Soviet assassination might
have been deemed out of the question if they hoped to avoid thermo-nuclear
war, surely a secret counter-plot to eliminate a Soviet leader would have
had to have been attempted in reprisal to let them know that such acts
would be dealt with in kind.