First how about you define what you mean by measurable, then we can see how you're gatekeeping the use of that term. Then define what you mean by impact to see how you're gatekeeping that quantification. Then maybe there can be a conversation.
We're talking about it - that's a measurable impact.
If you want to argue it didn't have a substantial impact then please provide proof that the media amplifying the Russia (and related narrative) as it has - distracting us from the real, underlying issues - wasn't substantial. Please prove that Russia's actions, including brigading Reddit and other communities via their propaganda farms, didn't provide talking points to the media to distract the majority of us from the important, underlying issues.
Perhaps you're trying to gate keep by limiting the scope by saying Russia's efforts didn't directly have a substantial impact? But then you're ignoring the full picture in order for your argument to be "more right" but still not correct; Russia's direct actions don't exist in a silo - likewise Trump would be nothing if mainstream media didn't amplify every insane word coming out of him.
As POTUS candidate Andrew Yang is pointing out to us: it's automation, not immigrants, that have been taking jobs leading to Americans suffering and lead to the symptom of Trump; as Noam Chomsky also rightfully pointed out, Netanyahu of Israel greatly interfered - directly - with American politics.
The mainstream media is directly and indirectly part of the dis-ease, and has allowed such dis-ease progression. Trump, a tyrant wannabe-never-will-be, understands this mechanism of mainstream media (reach, the attention economy, manipulation) - in general called marketing, Trump being a charlatan or false prophet vs. a genuine entrepreneur with true compassion - an ideal example being Yang to contrast Trump to, regardless of what you think about his policies, how he holds himself, his character.
Curious what your thoughts are, what your response will be.