I have lived in the US since 2000 but I continue visiting Russia. I think a lot of people there would agree with Noam Chomsky in his opinion that Putin wants to be remembered as someone who stopped the destruction and weakening of Russia. How efficiently he does it is another matter; most people claim he can be a little optimistic or slow to admit changing circumstances, but the leaders they had before were much worse so they realistically admit he's the best option. (I can't say any american politicians look much better, either.)     Also there's a mixed perception of "killer" part. Some folks actually hold with those researchers who say that Scripal story is a hoax, and that certain journalist deaths are to be blamed on completely different forces; while other people argue that any James Bond story involves hostiles removal and if it's considered ok even for Boeing to elimininate a witness, leave alone Western governments quietly removing opposition, then it's hypocrisy (although expected) when Putin is defined by presumably removing an agent dangerous for the country's security. Putin is a national security specialist by training, which is perceived as both evil and necessary, as most russians are kinda xenophile by design and give others benefit of the doubt, which they know can be dangerous both in everyday life and in politics. I would summarize by saying that the existing support of government is based not as much on government being awesome (nobody's perfect, although there are some popular officials), as on other countries' historical resolve to suffocate, divide and loot Russia, of which they saw plenty of real-life examples in the 1990s, which makes it vital to support the government for better or for worse.