I don't think there's any evidence that the US is involved, which of course means nothing, especially if any involvement is done "well". It's hard to say though, since Chavez was pretty heavy on the anti-American imperialism rhetoric and I think Maduro is too. I won't say that I'd be surprised at some involvement, but consider that Maduro only won by a 1.5% margin (so I've read) and generally seems to have been at a disadvantage from the get-go. Following Chavez has got to be tough. As for Lopez, I'm interested to know myself. From the brief articles I've read, it mostly seems that he's running on a platform of "I'm not Maduro" which might be enough. Anyway, allying himself with the student protesters is a smart move regardless of his platform. Hopefully he actually does have the people's interest at heart.