What are they purchasing though? Israel gets a massive missile defense system and the guarantee that no matter what they do to Palestine the USA will ensure there are no consequences.
Russia gets, what, to troll and goad the liberal media? To keep Maddow in a job?
What Russia is doing in the Ukraine is horrific, if a few troll farms can lead to the entire of the USA to breakdown then thats on the USA.
I guess a few things.
The obvious ones that directly affect the ruling class are sanctions and trade restrictions. The US enables market access, any disruption of that costs people money.
Whatever drives the US to promote their vision of liberal capitalist democracy onto others, something similar is driving an anti democratic authoritarian world view within the current ruling party in Russia. Similar to the US world view, Russia has their world view: democracy is a waste of time / all political parties are the same / all politicians are corrupt / strong man politics / any type of GLBT stuff is bollocks and so on. It's sort of hard to understand why the US or Russia wants to inflict their ruling party's values on others, but they do it.
Also similar to the US, empire building / expansion of power / permission slips for having wars. (They wanted that war / it's a war to save them / it's not really a war.)
Destabilization / divide / zero sum game stuff, polarizing groups within the US to be at each other's necks / Brexit etc results in splitting and paralysis in traditional centers of power, which increases their relative power.
Putting it glibly "money and power". But it's a bit more than that, the US is an empire with weird empire wants, and so is Russia. It's difficult to understand why the US feels the need to do some of its weird empirey things, but they do do them. It might be a kind of future proofing? We don't know exactly what's coming, but if we can control how people think we're more likely to be able to deal with it.
I guess what I learned in DC is that virtually every interest has lobbyists in DC. Even if you're not big enough to directly lobby, say some caribbean country, you'll band up with say a group of other central American guys and act that way. There's countless decisions being made every day, and if you can sway a fraction of a percent of them then it's worth it. It can and is as tiny as someone getting drinks for someone, someone getting some out of marraige hot sex, that leads to a banana and sugar cane factory loan (I think?). If you are in DC long enough you'll end up with lobbyists, in parties, getting drunk, and what happens there influences... I mean, anything from sugar cane deal upwards. Ahead of time you don't plan it out, you can't see the future, but you put all the pieces in play to make sure you get closer to the result you want. But yeah, EVERY decision made in DC is influenced by lobbyists. And Russia isn't going to be the single entity to stand above it all and decide they can't stomach it.
Having said that, I didn't actually go to parties and so on with Russian lobbysts doing work in the open, I didn't actually watch them work in the way I watched the Israel lobby / south american lobby / carrib & central american ones. I can't say I saw it that way, the closest was at a weird Dem new year eve gig momentarily that was Russian centric, but left because it was out of my depth, not dressed for it, and uncomfortable.
Sorry for the fucking length of the post... too tired to edit.