Russian military intelligence, the GRU, has always had an adversary relationship with KGB, state security, and in particular with KGB's foreign directorates. (Now known as SVR; the domestic side of the shop is the FSB.) GRU has an unhappy reputation for being ham-handed, and some of their more recent adventures seem to bear that reputation out. The poison attack on Sergei Skripal, in the UK, was reportedly a GRU operation, and certainly there have been others. But this quite possibly misses the point. Far from hiding their light under a bushel, GRU is going out of their way to sign their name.
(In my Cold War spy thriller Black Traffic, KGB general Rzhevsky uses GRU as a patsy in a deception operation, and refers to them as the 'Boots.' I didn't make this up. KGB has always thought these guys were knuckle-draggers.)
For all that Vladimir Putin himself is former KGB, he doesn't have a soft spot for his old crew. GRU and Spetsnaz units were deployed in Donbass and the Crimea, both as irregulars and in uniform, and got results. GRU's higher visibility and preference for muscle over mind looks like a sales strategy. It's no secret Putin favors the blunt instrument, but the new wrinkle here is the lack of plausible deniability. In the past, there was at least the pretense of maintaining a cover story. These days, nobody even makes the effort. The reasoning is brutally simple. Terror tactics don't work unless you show your handwriting. Give fear your own face.
Assassination as a covert means has a long history, but let's confine ourselves to living memory. Everybody's practiced it. CIA probably had a hand in Patrice Lumumba's death, and famously tried more than once for Castro. Mossad went after Black September, and decapitated the PFLP. It depends, to some degree, on whose ox is being gored. And you can argue that Israel, for example, is addressing a direct threat to its existence. But that's a kind of moral relativism. All the same, making it policy to murder reporters - instead of some guy who can design a gas centrifuge - is kicking it up a notch. Which brings us to Jamal Khashoggi and the Saudi royal family.
Again, we have the Russian model to follow. Putin has supposedly sanctioned dozens of killings, aside from defectors, the Skripals and Litvinenkos of this world, but people like Anna Politkovskaya, who was targeted because of her writings about the Chechen wars, and her opposition to Putin's rebranded Stalinism. She's just one example, of course, and her death only painted on the radar because she was so visible, and her killing so obviously retaliation.
What makes the Khashoggi murder different, and why it's getting so much press, is that the Saudis set a trap for him, at an embassy in another country, killed him, and lied about it without the slightest embarrassment - clearly not expecting anybody to ask questions, because the lies were so obvious. They not only don't give a rat's ass about the consequences, they don't in fact understand what all the fuss is about. Khashoggi was a fly buzzing around the room. We smacked him. What do you care? In this sense, it's not even the murder itself that's startling, it's the Saudis acting aggrieved, as if they're the ones who've been done the injury. Sorry to say, this is genius.
Further reading, Christopher Dickey in The Daily Beast: