The phrase "argues somewhat" is correct and usable in written English.
It can be used when indicating that someone is making a point or claim, but with a degree of uncertainty or moderation.
Example: "In her essay, she argues somewhat that the policy changes could have unintended consequences."
Alternatives: "contends to some extent" or "asserts to a degree".
Mr. Marino argues, somewhat counterintuitively, that Goldman should pay Mr. Aleynikov's legal fees because the allegations against him involved illegal activity while on the job.
The problem, Lambert argues (somewhat anecdotally) "reinstating the two-line pass won't prevent concussions because two-line passes, as far as I've been able to figure out, have never actually caused one".
A prime example of imperial overstretch, the United States faces a highly uncertain future, Mr. Khanna argues, somewhat more coherently, with economic decline and waning international influence distinct possibilities.
Raz argues, somewhat paradoxically, that, though law claims this authority, it generally does not have it.
(For a variant usage of this term, see Moore 1953, who there uses the term "sense-datum" to stand for whatever it is that is immediately experienced or given, possibly even a public physical object, and then argues somewhat tentatively that the entities that actually have this status are sense-data in the more usual sense, rather than physical objects).
The very weak SRA, which was performed during the second platelet count fall, argues somewhat against this patient having HIT.
Officials with Mr. Putin's political party, United Russia, have argued somewhat breathlessly that decisive action is needed to stop the spread of radicalism.
Contentious doc arguing (somewhat one-sidedly) in favour of nuclear power as a solution to climate change, and talking to experts and environmentalist converts.
But Key has resisted the argument that the debate is empty symbolism, arguing, somewhat implausibly, that a change in flag "has got to be worth billions over time" in brand recognition.
But his lawyers have argued, somewhat counterintuitively, that he was nevertheless given immunity from prosecution for his crimes by a federal prosecutor, Jeremiah O'Sullivan, who has since died, and that they wanted Mr. Bulger to explain the details at his trial.
Sir Nicholas put his charm to work, not only in the corridors of power but also in more than 60 appearances on American television, emphasizing Britain's historic ties with the United States and arguing, somewhat dubiously, as some of his British colleagues acknowledged later, that the Falklands conflict should be seen as part of the cold war struggle with the Soviet Union.
