WASHINGTON -- Leaders of both major parties are wrong to think of the 2016 election as some kind of fluke. I believe a political realignment is underway, and those who fail to discern its outlines could end up powerless and irrelevant.

With all respect to Hillary Clinton, her newly published memoir, "What Happened," doesn't really tell what happened. It is perhaps inevitable that she would focus on the daily twists and turns of the campaign. It is understandable that she would blame James Comey, Vladimir Putin and the media for damaging her prospects -- and that she would downplay her own strategic and tactical missteps.

But take a step back and look at the election through a wider lens. Clinton, with all her vast experience and proven ability, was defeated by Donald Trump, a reality television star who had never before run for office, displayed near-total ignorance of the issues, broke every rule of political rhetoric and was caught on videotape bragging of how he sexually assaulted random women by grabbing their crotches.

That's not just unlikely, it's impossible. At least it should have been, according to everything we knew -- or thought we knew -- about politics. Yes, Comey's last-minute revival of Clinton's email scandal robbed her of momentum. Yes, her neglect of the Rust Belt was a terrible mistake. Yes, the Russians were working hard to defeat her, with the blessing -- and at least the attempted collusion -- of the Trump campaign.

But the election never should have been close enough for relatively minor voting shifts in Wisconsin, Michigan and Pennsylvania to elect the likes of Trump. The election never should have been close enough for Clinton to lose Florida and barely eke out a win in Virginia.

In retrospect, the alarming possibility of an election-night surprise should have been apparent. Trump never should have won the Republican nomination over a field that included so many talented politicians. And Clinton never should have had to work so hard to win the Democratic nomination over Bernie Sanders, an aging socialist from Vermont who wasn't even a Democrat until he entered the race.

None of what happened should have happened. And it is a mistake to blame Clinton's character flaws, Trump's mastery of Twitter or the media's compulsion to chase every bright, shiny object. Something much bigger and deeper was going on.

My view is that the traditional left-to-right, progressive-to-conservative, Democratic-to-Republican political axis that we're all so familiar with is no longer a valid schematic of American political opinion. And I believe neither party has the foggiest idea what the new diagram looks like.

I don't think Trump can see the new spectrum either, as evidenced by the way his approval ratings have plunged since his inauguration. But both he and Sanders deserve credit for seeing that the old model has outlived its usefulness.

Look at the issues on which Trump and Sanders were in basic agreement. Both doubted the bipartisan consensus favoring free trade agreements, arguing they had disadvantaged U.S. workers. Both spoke of health care as a right that should be enjoyed by all citizens. Both pledged to strengthen, not weaken, entitlement programs such as Social Security and Medicare. Both were deeply skeptical of U.S. involvement in foreign wars, vowing to do their nation-building here at home. Both advocated mammoth, job-creating investments in infrastructure. Both contended "the system" was rigged to favor the rich and powerful at the expense of everyone else.

Leave aside for the moment the fact that Trump has not fulfilled his promises. The overlap in what he and Sanders said they would do is striking -- as is the contrast between what both Clinton and Trump's GOP rivals were saying.

Trump was uniquely transgressive on one issue -- immigration. He addressed the anxieties of white working-class voters by presenting immigrants as all-purpose scapegoats.

The Trump and Sanders campaigns revealed that there are large numbers of voters whose views are not being reflected by Democratic or Republican orthodox positions. Are the parties adapting? Democrats seem to be inching toward support of truly universal health care, while Republicans have thus far thought better of taking health insurance away from millions of people. Perhaps this is a start.

But I see no evidence yet that either party is engaged in the kind of fundamental rethinking I believe is called for. So it is a mistake to assume that Trump is necessarily a one-term president or that Sanders is done politically. You know the saying: In the land of the blind, a one-eyed man is king.

(c) 2017, Washington Post Writers Group