At some point, the question needs to be asked: How can congressional Democrats, handed a 400-page narrative filled with impeachable offenses by the president of the United States and then not-so-subtly nudged in a confrontational direction by its author, not open an impeachment inquiry in the House of Representatives?

House Speaker Nancy Pelosi has already given us her answer: because the Republican-controlled Senate will never vote to convict President Trump and remove him from office, and an impeachment that ends in acquittal on a party-line vote will only bolster the president's political hand by rallying his supporters as the country approaches the 2020 president election.

But how does she know this?

That she and a not-inconsiderable number of leading Democrats are quite certain that they do know it is revealing, showing us just how cramped and unimaginative their understanding of politics has become.

There are, broadly speaking, two styles of small-d democratic politics.

The first is responsive, seeking to gauge public opinion as it currently stands and to conform to it, giving the electorate what it says it wants and demonstrating caution and skittishness about defying it. This style of politics is often preferred by party institutions and sometimes the network of organizations in civil society that support the party's agenda and priorities. Both worry about losing their power and privileges and suspect that this will happen if they cross public opinion, which is treated as given and static.

The second style of politics is bolder and more radical, not necessarily in substance but certainly in the sense of a willingness, and even eagerness, to break away from the status quo. It imagines other configurations of public opinion, and uses arguments, ideology, and appeals to what it speculates to be people's inchoate but thus far unexpressed and unarticulated desires and needs, promising to respond to them before the electorate even realizes it has them. This work is usually done by activists and intellectuals outside the party apparatus who aim at “creating a public” in support of policies when one does not yet exist.

The phrase “creating a public” comes from author Corey Robin. He invoked this second style of politics in an important essay from a few years ago about the need for intellectuals and activists to recognize their capacity to help change public opinion rather than just respond to its current configuration.

Over the past few decades, the Republican and Democratic parties have taken very different stances toward these two styles of politics. The Reagan revolution was achieved in large part by creating a public in favor of the president's distinctive blend of economic libertarianism and cultural conservatism, but that quickly became the default position of the institutional Republican Party, which has tended to operate in the first, responsive mode of politics.

Conservative activists, media figures, and some elected officials, though, never gave up their ambitions to push public opinion even further to the right, beyond what Reagan himself managed to accomplish. Newt Gingrich, Rush Limbaugh, Fox News — they and many others have never let up. And it's worked, with the institutional party often in the position of doing the work of responding to and consolidating each activist-driven rightward shift in public opinion.

The process worked without a glitch until Donald Trump leapt far ahead of public opinion beginning in the summer of 2015, breaking from institutional party orthodoxy on several fronts — immigration, trade, and foreign policy — and in the process creating a public that approved of the change. At first, that left the institutional party confused, then in notional opposition, but then finally playing catch up as it sought to enforce the new dispensation. Now the institutional party responds to fully Trumpified public opinion on the right.

In comparison, Democrats have been much more cautious, far more wedded to the responsive, passive approach to public opinion. That's one way to understand Clintonism — as a form of Reaganism-lite, tailor-made to appeal to where the Democrats found public opinion in 1992, after three terms of GOP presidents. Even Barack Obama's presidency can be seen this way. It deployed much loftier rhetoric than Bill Clinton did in the '90s or Hillary Clinton would in 2016. But that rhetoric — with its talk of contentless change and vague focus on the person of Obama himself — didn't do much to create a public to support an ambitious left-of-center policy agenda.

Today, the Democrats are divided, with the left wing of the party, especially the presidential campaigns of Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (D-Mass.), eager to do the work of creating such a public, but much of the institutional party, along with Pelosi and the front-running campaign of Joe Biden, largely uninterested and sometimes downright resistant. (Strangely, Trump is such a forceful and polarizing figure that he appears to have done far more than the Democratic Party itself in creating a public on the left — with, for example, rising support for immigration most likely a function of a reaction of Trump’s cruelty and bigotry on the issue.)

And that brings us back to impeachment.

It's true that at the moment, the Democratic Party's voters appear to be divided on whether to initiate impeachment proceedings against the president. But that didn't stop Warren from coming out early on in favor of doing precisely that. In the weeks since she made that calculation, her standing in the polls has slightly improved. There could of course be numerous reasons for that. But one of them may be that she took a risk and stuck to her guns, making the case for impeachment a part of her campaign and message to voters.

The very process of holding impeachment hearings and presenting evidence buried in the Mueller report would do the same thing on a much grander scale and before a vastly greater national audience. Would that buoy Trump's reelection prospects? Possibly. But it could also go the other way, persuading thousands and potentially millions of Americans — including even an indeterminate number of Republican senators — to ponder and judge harshly the actions of the president and his 2016 campaign.

Public opinion isn't static, and it isn't only changed by factors beyond the control of political actors. Those actors can help to bring about the change they seek with what they say and what they do — by using their political imaginations to paint a picture and invite voters to imagine it along with them. That isn't some esoteric, or even an especially controversial, political truth. It's a basic fact of democratic politics — though also one that too many powerful Democrats appear to have forgotten.