More like an earthquake than a hurricane, the remaking of America’s political parties hit without warning. At least no alert was detected by the seismometers or twitching antennae of the certified experts of political science. (Or those who still insist politics really is a science.)

Yet, make no mistake, the remake is real. It is a rework-in-progress. And it wasn’t detected until the politicos felt it happening in Tuesday’s 2017 election.

The political earth moved for the Democrats, most climactically. And that shook the Republicans, most distressingly, as Democrats won, in scattered races everywhere the off-year elections were held:

In Virginia, Democrat Ralph Northam was elected governor with a 9 percentage point margin that was the party’s biggest in 32 years. Virginia’s Democrats triumphed all the way down the ballot, including flipping 14 GOP-held state house seats. In New Jersey, where Democrat Phil Murphy’s unsurprising win ended the era of the unpopular Republican Gov. Chris Christie. Even in reliably Republican Georgia, Democrats captured three GOP-held state house seats.

No wonder the 2017 electoral aftershocks are the topic of shattering priority (bordering on semi-panic, for some) inside every Republican inner sanctum. Today we will discover the true magnitude of just what happened — and why.

The quick-and-easy TV punditry made the obvious perfectly clear: Independents and even Republicans nationwide were rebelling against President Donald Trump’s combative, untruthful and bullying ways. Indeed, Virginia’s voter exit polls showed that 57 percent of those voting disapproved of how Trump is performing his job; and unsurprisingly, Democrat Northam received 87 percent of those votes. Gubernatorial candidate Ed Gillespie, a longtime Republican strategist and lobbyist, won the votes of almost all of the 40 percent who said they approved of Trump’s job performance. But exit polls cannot measure the views of those stayed home because they are turned off by Trump’s unpresidential conduct.

Time out for a personal observation: I’ve known Ed Gillespie for decades and always found him to be a straightforward and personable pol. But I was astounded at the bizarre, and reprehensible way Gillespie closed out his campaign. He chose a Trump-styled appeal emphasizing conservative base-driving, non-substantive issues (i.e.: not removing Virginia’s confederacy statues). And his TV ads included a fear and smear demagoguery ad aimed at scaring Virginians by claiming Northam favored restoring the rights of a man convicted of child pornography charges. But Democratic Gov. Terry McAuliffe’s program that Northam backed restored rights to permit voting, serving on juries and obtaining firearms. Left unsaid was that Gillespie, in his responsible past, also favored restoring rights of convicted felons.

Virginians surprised me. After newspaper editorials blasted his ads, Gillespie wound up losing many college-educated voters, especially suburban white women who last year voted for Trump.

But Virginia’s exit polls also revealed a most significant lesson for nationwide Republicans (even though it was overlooked by pols and pundits). While strategists push their negative attack ads, we just learned that people really care most about the things that affect their families most. (Repeat in unison: Duh!)

When exit pollsters asked people which of five issues mattered most as they decided whom to vote for, Virginians overwhelmingly named only one — health care. It scored 39 percent; all others (gun policy, taxes, immigration, and abortion) scored in the teens or lower.

Most importantly: 77 percent of those listing health care as most important in their choice then voted for Democrat Northam. Only 23 percent who cited health care voted for Gillespie.

This tells us is the real blame for Tuesday’s Republican defeats is more than just disgust with Trump’s presidency. Senate Majority Leader Mitch McConnell, House Speaker Paul Ryan and the entire GOP congressional leadership must share the blame — because they failed to protect Americans’ health care insurance. Voters realize every idea the GOP leaders pushed in the guise of repealing and replacing Obamacare would cause millions of middle-class families to lose their health insurance, independent analysts said.

America’s working class families — including Trump’s Republican voter base — saw their GOP leaders playing partisan politics rather than working with Democrats to fix Obamacare’s flaws and saving what works best.

Tuesday’s real message for Republicans was unmistakable: Their own working class base fears losing their health insurance security. Yet, when it came to safeguarding the security fears of their own hard-working Americans, the once-Grand Old Party has shown it is no longer grand, nor even good. The GOP leaders don’t care — and the people get it.