Bob Shrum is one of America’s most veteran political campaigners. His work for Democrats has extended over half a century, culminating in his central role in John Kerry’s campaign in 2004. He is the author of a sparkling memoir, No Excuses: Concessions of a Serial Campaigner. Whenever I want to understand what’s most likely to happen in American politics, Shrum’s is one of the voices I listen to most carefully—and not just because of the accident of rhyming last names that makes us sound like a Dickensian law firm. He and I exchanged emails on the afternoon of May 16.

David Frum: Hello Bob, I’m glad to renew the Frum-Shrum dialogue after too long a lapse. Let’s start with some basic election mechanics, and then work outward to broader themes. I proposed in a piece for The Atlantic this weekend that, with only a few not especially heroic assumptions, you can create a Trump victory scenario in the electoral college:

A) Trump runs equal to Romney will college-educated white men; Hillary fails to improve much on Obama’s numbers among college-educated white women;

B) Noncollege whites turn out in significantly larger numbers for Trump than for Romney, not only because of the trade and migration issues, but also because of Hillary Clinton’s outspoken advocacy for gun control, which will hurt in Pennsylvania and Wisconsin;

C) The Latino gender gap—already the widest of any ethnic group—widens further in a Hillary Clinton-Donald Trump contest, enabling Trump to run better among Latino men (especially young Latino men) than either Romney or McCain—even as Hillary matches Obama’s high support among Latino women.

Result: Trump wins all the Romney states of 2012, plus Colorado, Ohio, Nevada, Pennsylvania (where he’s running close), and Wisconsin. That takes him to 269 electoral college votes, if I’ve done the arithmetic right. If he can add Florida or Virginia to that tally, he’s the president. What do you think?

Bob Shrum: I think that's close to impossible. Trump has an 87 percent unfavorable rating among Latinos, 91 percent with African Americans, and somewhere between 65 and 70 percent with women. He's in a demographic cul-de-sac and I don't see how he works his way out. For every white working-class vote  he picks up, he will lose one or more suburban independents or even Republicans.

Last summer, I argued that he had a real chance to win the Republican nomination, given  the party's strategy in 2010 and 2014, which ignored John F. Kennedy's warning in his Inaugural Address that "those who ride on the back of the tiger often end up inside." That's what happened this year with the Republican base, disillusioned with its leaders and in disagreement with them on policies like entitlements and  immigration reform. In the process, conservatism became less set of policies and principles that a set of angers, alienations, and grievances. Trump was ideally positioned to exploit all that. He is a very talented politician—or demagogue—depending on your perspective. But  he will now pay a price for his success inside the GOP and I am as sure that he is unlikely to win in November as I was that he could win in the primaries.

Frum: Let’s riffle the cards the other way. Supposing things go as badly as the current polls suggest, with Trump running about 6 points behind Hillary Clinton—that’s a defeat in the 2008 Obama-McCain range, not in the 1984 / 1972 / 1964 range, right? Which suggests (if those poll numbers hold) that although Republicans may drop a seat or two in Senate, maybe lose some in House, the final outcome of this ultra-dramatic election would be … more or less the status quo? Or do you see it differently?

Shrum: The country is certainly more polarized now than in 1964 or 1984, so it's possible that the Clinton win is relatively modest. I doubt that though and I think we should concentrate on the battleground states, where there are  also serious Senate contests. Political prognosticators like Charlie Cook and Larry Sabato have shifted a whole range of these states toward Clinton. One entirely reasonable assessment by Dave Wasserman sees Democrats increasing their vote in all 15 of the states he analyzed. The best guess is the Democrats do take the Senate—and that Hillary Clinton wins by more than six or seven points, which in this era would be a considerable margin in any event.

Frum: To widen the aperture a little, the question I’m driving at is: How big a deal is this election going to prove, ultimately?

Since 1992, we’ve lived through a political era characterized by the following:

A) polarized and relatively close presidential elections, with a small but decided advantage for Democratic candidates;

B) a Republican advantage in Congress, especially the House, and in state races;

C) gridlock as the norm, punctuated by rare moments of ultra-activism (1995, 2002-03, 2009-2010).

Will 2016 be the next chapter in this story? Or could America be at a break moment—a 1968—when one political chapter ends and another starts?

Shrum: You may be right—unless Trump melts down. A President Hillary Clinton could certainly face the same kind of gridlock that we have seen for the last five and a half years. But on some issues we would see movement; the Supreme Court, for example, would acquire a ninth justice. Ironically, that could benefit Republicans by putting contentious social issues that disadvantage them pretty much to rest. Legislatively Clinton would try to reach out and find some areas of agreement. That didn't work for Obama and it might not work for her. On the other hand, if the GOP loses decisively in 2016, political necessity may push the party toward being a governing instrument again. That would put the leadership at odds with gerrymandered members who elevate ideology above all else, and seen instinctively hostile to any Democratic president, especially one named Obama or Clinton. If I'm wrong and somehow Trump wins, there may be a different kind of gridlock—not only between him and Democrats, but between him and many of his fellow Republicans. (That assumes, of course, that he is a Republican in anything but name only.)

Frum: It’s not a matter of me being “right”—because my own view is that 2016 is shaping up as a chapter-ender. Look at the Democratic side, for example. Ronald Reagan was able to hand his party’s nomination more or less uncontroversially to his closest associate, George H.W. Bush. Barack Obama is at least as popular in the country as Ronald Reagan was in 1988, and perhaps even more dominant in his party … And yet Obama’s closest colleague is facing an all-out insurrection that still hasn’t quelled. That insurrection expresses a radical critique of the Obama presidency. It’s also unmistakably racially based: Bernie Sanders dominates among white Democrats; Hillary Clinton among minorities. Actually, Revolt of the White Democrats would be a good title for a book about the Sanders challenge.  

And of course on the Republican side, the break with the party’s past is even more radical and abrupt.

Shrum: David, in one sense I think of you as always "right" but never far right. In my view, the insurgencies in the two parties are quite different in character. Democratic dissatisfaction is driven primarily by economic conditions. The economy is improving—13 million new jobs have been created—and incomes are actually beginning to rise. But that has not been fully felt yet and the Sanders movement is amplified by millennials who are naturally attracted to an insurgent, and for whom the cost of college is a dominant issue. But most Sanders supporters will come home to Clinton as the Democratic nominee. The differences between them are not fundamental—and as Sanders says, she is clearly preferable to Trump, who will be the great unwitting unifier for Democrats. Not since the founding fathers has someone prominent, genuinely prominent, in the public eye for 24 years been elected president; it appears that will change with Hillary Clinton. The early GOP front runner succumbed to Bush fatigue; she did not experience a similar downfall. In contrast, I believe that the Republican revolt that produced Trump has deeper causes—not just economic, but a sense of frustration about the sweeping cultural and social changes in the country. The Trump constituency is on the wrong side of history—and the Republican Party will have to come to terms with the changing America or face sharply diminished odds of winning the White House at any point in the near and medium-term future barring a serious economic or foreign crisis.

Frum: Millennials are as divided by race as any other age group in this country—and possibly getting more so. Romney won non-Hispanic whites under 30 in 2012, and I would not be surprised if Trump won them by an even larger margin in 2016. I think you are absolutely correct about role of economic dissatisfaction … but economic concerns are also inescapably filtered through ethnic and cultural divisions too. And one big theme of this year is that “white Americans” are now functioning as something very like an ethnic group, with Bernie Sanders and Donald Trump acting (in very different ways!) as their champions—and for that reason, being forgiven a lot of very gaping sins by their supporters, as ethnic champions so often have been in American history. (See former Atlantic editor Jack Beatty’s marvelous The Rascal King for a definitive portrait of this excuse-making at work.) American elites have engineered a more diverse country. They are now discovering that they don’t know how to govern it.

Shrum: Bernie Sanders’s support is not driven by race. He does better with white voters, including young white voters, because Clinton has long-standing and deeply rooted ties to the African American and Latino communities. That is a strength for her, not a weakness. So I profoundly  disagree that the Sanders and Trump cases are comparable. Part of the resentment that fuels Trump, and he plays to it, is race-driven. There are Americans, a minority of Americans, who are disoriented and angry about the reality of a nation where whites soon will no longer be the majority. That has already happened in California. I see it as part of the ongoing American journey—a country defined not by race or geography, but by an idea that can and should encompass diversity. Resistance to this is recipe for political defeat—and as expressed by Trump, represents an appeal to the darker side of American history and the darker  impulses of the American spirit. Diversity is in our national genes; it was engendered—in our founding documents and in Lincoln's determination to make the nation live up to its ideals. It is a shame the Republican Party has forgotten that—maybe the process started with Nixon's Southern Strategy—but it has culminated in the almost certainly unelectable Donald Trump.

Thanks for a provocative and intriguing conversation.