New York (CNN Business) Here's a poll question. Think about how you would answer it.

"So far, do you think Mueller's investigation has or has not proven that Russia tried to interfere with the 2016 presidential election?"

The Washington Post and the Schar School asked 841 adults this question last week, and the results were right down the middle — a reflection of a country split between two competing realities.

Among all adults, 43% said special counsel Robert Mueller has proven the Russian interference plot. Another 43% said he has not proven it. The remaining 14% had no opinion.

Ask almost any journalist who's covering this subject, and they'd say the evidence of Russian interference is overwhelming. The attack happened right out in the open, and the residue still exists on social media platforms like Facebook and Twitter.

But President Trump's constant denials of "collusion" and his contradictory comments about Russia have sowed a tremendous amount of doubt and confusion.

"It's really remarkable that the 2016 Russian election interference could still be viewed as an open question at all," said Susan Hennessey, the executive editor of Lawfare and a CNN national security and legal analyst. "Reasonable minds can differ on whether public evidence supports the idea that the President or his associates conspired in the effort, but there is just no question regarding what Russia did."

Hennessey pointed out that there was "substantial forensic evidence" of Russian interference even prior to Election Day in 2016. The US intelligence community "concluded with high confidence that it occurred," Hennessey said. Trump's own national security officials have affirmed this. And some of Mueller's indictments have contained even more evidence of Russian information warfare efforts.

But questions about Mueller, Trump and Russia are intensely polarizing, to put it mildly. In a new analysis on Wednesday, the polling website FiveThirtyEight said " public opinion of the Mueller investigation has become more partisan ."

"Unless there's a real bombshell in whatever report comes out of the special counsel's office, the end of the investigation may not bring sweeping changes of opinion," Dhrumil Mehta wrote. "Instead, we may just see the public dig in their heels and retreat to their partisan corners."

Lee M. Miringoff, the director of the Marist Institute for Public Opinion, told CNN Business that the Post's survey question "is tapping into a similar number that Trump gets on his approval rating."

CNN's latest poll of polls has Trump at 39% approval.

Miringoff made the case that polling questions about Mueller's findings "may be getting a little ahead of the story," given that "there has been next to nothing coming out of the investigation."

So the question "is in effect measuring Trump versus investigation," Miringoff said.

Past surveys have found that some Trump supporters are loath to acknowledge Russian interference, lest it seem like they're doubting the legitimacy of Trump's election.

And media coverage makes this worse, "Cyberwar" author Kathleen Hall Jamieson asserts.

She said coverage "tends to conflate the questions — 'Did the Russian efforts affect enough votes to change the outcome?' with the question 'Did the Trump campaign coordinate with the Russians?' Difficult to know whether the public is actually hearing one of these two questions when asked that specific polling question."

In the Post poll, which has an overall margin of error of 4 percentage points, there was a predictable divide among party identification.

Only 19% of Republicans said they thought Mueller has "proven" that Russia tried to interfere in 2016, versus 66% of Democrats.

Among independents, 42% said Mueller has proven it, and 42% said he has not.

"Those poll numbers reflect the extent to which President Trump has been successful in convincing portions of the American public to simply ignore and deny facts that are inconvenient to him," Hennessey said.