Things of value
I've seen this claim previously. It basically swings on whether opposition research (also called dirt on a political opponent) is a "thing of value" in the context of the law. Most analyses I've seen have depended on what the person doing the analysis thought of Donald Trump, which makes them questionable.
Can "thing" be something intangible? Or does it have to be something with a physical representation? The first two possibilities relate primarily to fiscal transactions, where there is a physical thing that can represent the transaction (even if the transaction only takes place in virtual form). We can represent the transaction with physical currency.
The pro-Trump analyst generally says that in this section a "thing" has to be something with a physical representation. That could be money, a car, or even an advertisement (which has a fiscal value). But it can't be something as intangible as information.
The anti-Trump analyst might argue that money and advertisements are also intangible.
Proof of conspiracy
My personal opinion is that precedent is on the pro-Trump side. Politicians like Bob Menendez, Bob McDonnell, and Bill Jefferson have had convictions rejected or reversed on much more solid evidence (actual tangible things).
It's difficult to prove a conspiracy. It's not enough to prove a quid and a quo (all three examples had that). They need to prove that the reason for the quid was the quo. I.e. they have to prove pro to make quid pro quo.
Another issue in this case is that there is no evidence that there was ever an agreement for the Trump side to do anything for the Russian side. The Russian side failed to provide the information they suggested existed. So even if it were decided that opposition research constitutes a "thing of value" under that law (which is itself a questionable assertion), they still might not be able to prove conspiracy because in this case, they lack quid and quo as well as pro.
If information is a "thing of value" in the context of that law, they would have a much better case against Fusion GPS, which gave actual money to Christopher Steele, a foreign national, in exchange for information. Note that the law there doesn't differentiate between foreign nationals of Russia versus the United Kingdom. Of course, many people might make a moral distinction.
Steele had the intent to affect the election. He openly told people that he wanted Trump to lose. From Vox:
In September 2016, Steele spoke with Deputy Attorney General Bruce Ohr. He told Ohr that he “was desperate that Donald Trump not get elected and was passionate about him not being president.” Ohr’s wife worked for the research firm, Fusion GPS, that hired Steele on behalf of the DNC/Clinton lawyer.
So we have quid (money went from Fusion GPS to Steele); we have quo (information went from Steele to Fusion GPS); we have intent (Steele intended to affect the election); and Steele of course is a foreign national.
Contrast that with the Trump Tower meeting on June 9th, 2016. No quid nor quo. No money, information, nor promises for the future were exchanged. There was no actual conspiracy.
Now, some people claim that such things did happen in that meeting, but they have no proof of that. That's why they're talking about much weaker claims, like going to the meeting to get opposition research (dirt on Hillary Clinton) was in and of itself conspiracy. But again, if that's true, that would apply even more to Christopher Steele. He was a foreign national giving information to affect the election. People took meetings with him specifically to get access to that information with the hope of affecting the election. Fusion GPS gave him money to help him get more information to use to affect the election.
Saying that intent was lacking is the Steele/Fusion GPS relationship is totally ignoring the actuality. They had the intent. What they lacked was the ability.
The claim that Fusion GPS paying for the information made it all right is absurd. In reality, that's simply more proof. Consider, what would have happened if the Russians had produced information in the meeting and Donald Trump, Jr. had paid them for it? Would that make it all right? That position essentially says that it is criminal to want to obtain such information and fail but legal to succeed.
It's easy to explain why the Trump team answered the way that they did. While digging up dirt on one's opponent is not illegal, it is unseemly. Politicians do not like looking unseemly. So they emphasized what actually happened in the meeting: they got a lecture on how the Magnitsky Act was blocking adoptions of Russian children in the US. They deemphasized that they had been hoping for dirt and in fact, that was the only reason they took the meeting. This may have been silly, as the story was almost certain to come out, but as amateurs, they may not have realized that.