Donald Trump poses a serious threat to our democracy. Hellbent on whipping up fear and resentment, Trump is running for president on a platform of visceral contempt — for immigrants, Muslims and facts — trafficking in insults rather than ideas. There should be little dispute that Trump’s unconcealed bigotry, proud ignorance and authoritarian tendencies make him singularly unfit for office. The question now is whether Democrats will allow him to make the election a mudslinging contest or offer the country a real debate about our future.

In peddling unsubstantiated claims of collusion between Trump and Russian President Vladimir Putin, Democrats unfortunately seem eager to join Trump in abandoning policy for posturing. Indeed, many Democrats are letting the very real dangers of a Trump presidency take a back seat to the notion that Trump is not just alarmingly unqualified but is, in fact, an agent of the Kremlin. Together with neoconservative Trump opponents who see an opportunity to regain relevance, they are turning the Orange Menace into a new Red Scare. This is both preposterous and dangerous.

The narrative that Trump is “Putin’s stooge” has been propelled by a series of recent events. First, the Trump campaign worked to keep the Republican platform from supporting “providing lethal defensive weapons” to Ukraine. Trump then told the New York Times that some NATO allies were shirkers, saying that he would not automatically commit to defending countries that haven’t “fulfilled their obligations to us.” And most explosively, in response to speculation that Russian hackers were responsible for leaking emails from the Democratic National Committee, Trump suggested that if the Russians had Hillary Clinton’s private emails, they ought to release them, too.

Trump’s remark about the email hacking, which he now claims was “sarcastic,” was clearly irresponsible. But now, egged on by neoconservative hawks and liberal interventionists intent on ratcheting up tensions with Russia, Democrats — including the Clinton campaign and its liberal supporters — are contending that Trump is a Manchurian candidate, perhaps even guilty of “treason.”

This is disingenuous. Democrats and their allies have failed to acknowledge that Trump’s opposition to sending arms to Ukraine is consistent with the Obama administration’s position. Nor have they grappled with the fact that President Obama has also characterized some of our European allies, accurately, as “free riders.” And while Democrats have eagerly promoted the rumor that Russia is meddling in the election to help Trump win, many U.S. intelligence officials remain skeptical. As one official told The Post, “We have not drawn any evidentiary connection to any Russian intelligence service and [the DNC hack] — none.”

Clinton's campaign manager Robby Mook refers to what "experts are saying" in regards to Russian state actors allegedly taking thousands of Democratic National Committee emails and says after a review, the DNC will "take appropriate action." (Reuters)

In their zeal to defeat Trump, Democrats are getting in the gutter with him — and as a result are on the verge of becoming the Cold War party, with Trump, ironically, becoming the candidate of détente. Many of the same people who mercilessly mocked Republicans for their fear-mongering about Russia in the last election are now resorting to rhetoric no more credible than Trump’s ridiculous promises to “build a wall” or “bomb the s--- out of” the Islamic State — calling Trump “Putin’s puppet,” for example, and warning that he would be “Putin’s man in the White House” if he prevails.

One of Trump’s many disturbing qualities is that, with his every utterance, he obliterates complexity. When it comes to complicated foreign policy issues in particular, what we need today are a more robust debate and a serious challenge to a bipartisan foreign policy establishment that has failed. Blind adherence to the portrayal of Russia as sole aggressor in Ukraine, failure to account for U.S. and NATO members’ role in worsening relations with Russia, and now dispatching more U.S. and NATO forces on Russia’s borders have left the United States careening recklessly toward a new Cold War. We need to change course before it’s too late.

It is simply sober realism, not pro-Russia or pro-Putin, to make the case that the United States has a real stake in working with Russia — on nuclear proliferation, on the Islamic State and terrorism, on security in Europe and on climate change. Already, the Iran deal that Obama and Clinton celebrate was made possible by Russia and China joining in international sanctions against Iran. It’s also true — even if Trump says it — that U.S. allies should bear their fair share of the burden of collective defense. Reconsideration of NATO’s role in the 21st century is long overdue. To disagree is one thing, but labeling anyone who makes such arguments a “stooge” is a form of neo-McCarthyism that chills debate and diminishes our public discourse.

This country faces serious challenges. Our politics are corrupted, our economy rigged to favor the few. Climate change is a real and present danger. We need a big debate about real things, and we need leaders who don’t wallow in insults and lies. Democrats are wrong if they let Trump lower this campaign to his level.

Read more from Katrina vanden Heuvel’s archive or follow her on Twitter.