Two impeachments and an internet later, impeachment polls have become, to appropriate a phrase from the novelist Don DeLillo, “a form of cultural hysteria.” DeLillo was referring to lists, but polls are seductive and reductive in many of the same ways. Today’s impeachment polls are a special dubious subset of the polling genre, owing to their sheer number, questionable purpose, and potential sway over Senate votes. They are multiple choice and minimal fuss, facilitating the distillation of partisan chaos and factual complexity into a tweet and a punch line. They are updated regularly and amalgamated daily, offering a nation of smartphone obsessives and Fitbit users the specious knowledge that comes of real-time data. Thanks to his colorful tweets, the American public knows President Trump is tracking the polls, too, and that, like the rest of the country, he swings between loving them and grieving them. Watching him watch them has become an essential part of this hollow collective ritual, of repeatedly taking the temperature of the body politic without checking for a pulse.

The point is not to dismiss public-opinion polling generally or data science specifically, or to rehash what Time magazine wearily described—in 1948—as “the debate over whether public-opinion polls are good or bad for a democracy.” Nor is it to deny that impeachment polling can yield some interesting insights. For example, a Quinnipiac poll released earlier this month showed that although only 7 percent of Republicans approved of the House’s vote to impeach Trump, 39 percent would like to see testimony from John Bolton, Trump’s former national security adviser. And this was almost two weeks before The New York Times reported that Bolton’s forthcoming book says Trump explicitly described his desire to withhold aid to Ukraine unless the country investigated his political rivals. As a point of comparison, 91 percent of Democrats both approved of Trump’s impeachment and want to see Bolton testify.

But an overemphasis on polling data, as Black’s warning suggested, is a problem to watch out for in an impeachment trial, because polls are not designed to merely measure the public's views on important issues. They also are intended to amplify them. And for a couple of reasons, the overemphasis may prove a particularly pointed problem for the trial that is now unfolding.

For one thing, the timing of Trump’s impeachment and trial has heightened the perceived need for polling data; how the public feels about his removal is an unavoidable question for the purposes of assessing the Republican Party’s chances of success in November. Although commentators like to emphasize that Trump’s removal is more popular than President Richard Nixon’s at the height of Watergate, targeted polls spotlight the preferences that matter: They belong to voters in battleground states like Michigan, Pennsylvania, and Wisconsin. This conflation of presidential ejection and election, combined with the frequency and granularity of modern polling, complicates and exacerbates the electoral pressures that Black feared would influence Senate votes.