Democratic presidential candidate Joe Biden on Saturday in Columbia, S.C. (Sean Rayford/Photographer: Sean Rayford/Getty)

Joe Biden stands out from other Democratic candidates not just by taking on President Trump directly but also by seeking to separate Trump from the rest of the Republican Party. The New York Times notes that on a recent swing through Iowa, Biden described the Trump administration as “an aberration” and said, “This is not the Republican Party.” He often makes references to his “Republican friends and even says that Vice President Pence and former vice president Dick Cheney — both considered boogeymen by the left — are “decent” guys. This has raised the hackles of more liberal Democrats who view Trump as the rightful and representative leader of an irredeemably evil party.

Who’s right? Biden or his critics? Let’s weigh the evidence.

Biden’s critics are right that Trump is more a symptom of Republican maladies than their cause. Though Trump is radically different from his Republican predecessors in many respects — viz., his nonstop stream of insults, his unapologetic criminality (as detailed by the Mueller report), his embrace of dictators, his opposition to free trade — in other ways, he is a chip off the old block. And not just because he is delivering on conservative judges and massive tax cuts whose benefits are tilted toward upper-income earners.

Trump’s overt racism (e.g., calling white supremacists “very fine people” and African countries “shitholes”) is simply a more unsubtle form of the Southern strategy that the GOP has pursued since the 1960s.Using offensive language, the legendary operative Lee Atwater explained in 1981 how this worked: “You start in 1954 by saying ‘N-----, n-----, n-----.’ By 1968, you can’t say ‘n-----.’ That hurts you. It backfires. So you say stuff like forced busing, states rights and all that stuff and you get so abstract.”

Trump’s poisonous invective — he accuses his critics of “TREASONOUS” acts and calls the press “the enemy of the people” — is rooted in the tactics pioneered by former House Speaker Newt Gingrich. In 1978, Gingrich said, “I think one of the great problems we have in the Republican party is that we don’t encourage you to be nasty.” To remedy that “problem,” he circulated a memorandum in 1990 encouraging GOP candidates to use words such as “sick,” “traitors” and “pathetic” to describe their Democratic opponents. Gingrich himself suggested that a South Carolina woman’s murder of her two sons in 1994 was the result of Democratic policies and called Democrats the “enemy of normal Americans.”

So, too, Trump’s disdain for bipartisanship and political norms has plenty of GOP antecedents. Sen. Mitch McConnell (R-Ky.), then the Senate minority leader, announced in 2010 that “the single most important thing we want to achieve” was not to pass legislation but to make President Barack Obama “a one-term president.” As majority leader in 2016, McConnell refused to grant a confirmation vote to Obama’s Supreme Court nominee, Merrick Garland, to hold a seat open for a Republican president to fill.

Even Trump’s irrationalism and conspiracy-mongering have deep Republican roots, dating back to Joseph McCarthy and the John Birch Society in the 1950s. Climate-change denialism had become a party litmus test by the time Trump said in 2012 that global warming was a made-in-China hoax. Starting in 2008, the Koch brothers labeled legislation to address global warming as “environmental political correctness” and persuaded GOP candidates to sign a pledge opposing “any legislation relating to climate change that includes a net increase in government revenue.” Denying climate change was a gateway drug for Republican irrationality. Before long, the GOP embraced Trump’s birtherism. (In a 2011 poll, 51 percent of likely Republican primary voters said Obama wasn’t born in the United States.)

I don’t want to push the continuities between Trump and previous Republicans too far. There are also major discontinuities. He certainly acts in ways that no previous Republican — or non-Republican — president has ever acted. But Republicans cannot plausibly dissociate him from his actions. Not when 90 percent of GOP voters support him. And not when Republican members of Congress vote with him more than 90 percent of the time.

Yet Biden is smart to pretend otherwise. To win in 2020, a Democratic nominee will need to win back voters in key Midwestern states who supported Trump in 2016. (Nationally, more than 9 percent of Obama voters cast a ballot for Trump.) Demonizing the entire Republican Party will only push these voters deeper into Trump territory — and deepen the partisan divide that is tearing our country apart. Trying to pry Trump apart from the GOP, on the other hand, can make it easier to win over the 32 percent of Republican and Republican-leaning voters who don’t want their party to renominate Trump. It will also make it easier after the next election to forge common ground with Republican lawmakers and try to repair the damage Trump has done.

The notion that Trump isn’t representative of the Republican Party may not be true, but it’s a useful fiction that Biden is right to embrace for the good of the Democratic Party — and the whole country.

Read more:

Jennifer Rubin: The media underestimates Biden’s strengths

Karen Tumulty: Joe Biden could be the best bet to beat Trump. But he might not get that far.

Henry Olsen: The GOP is the party of Trump — but not for the reasons anti-Trump conservatives think

Paul Waldman: No bottom: Republicans show they’ll defend just about anything Trump does

E.J. Dionne Jr.: History will mark how many Republicans shy from Trump’s extremism