A woman holds a sign encouraging voters during a Women’s March rally in Las Vegas on Jan. 21. (Steve Marcus/Reuters)

The Post reported this week:

In 2017, the number of people who identify as Republican dropped off. The number of people who identify as Republican-leaning independent stayed about the same, and the number who identified as pure independent went up.

It’s often the case that political transitions happen gradually. In a presidential race, people usually don’t switch from one candidate to the other; they make a pit-stop in “undecided” first. It’s possible … that a number of Republicans began to identify as Republican-leaning independent as a number of Republican-leaning independents decided not to lean that way anymore.

There are fewer President Trump supporters in part because there are fewer Republicans: “In January 2017, about 156 million people approved of Trump on average, more than half of them — 81.2 million — Republican. (For each month, we averaged the available values.) That’s out of about 91.2 million Republicans overall. By December, about 125 million people approved of Trump, with more than half again coming from the Republican Party. There were about as many Republicans in total in December as approved of Trump in January 2017.” Trump has focused almost exclusively on his base, but his hyper-partisan ethno-nationalism means that “his party eroded over the course of 2017, which, given his margin of victory two years ago, bodes poorly for a reelection.”

This doesn’t mean Democrats have won these voters over. It does, however, mean that these voters could be won over in the midterms and beyond. Democrats need to think seriously about how to appeal to those voters Trump has shaken loose from the GOP.

Democrats would do well to recognize who these voters are. Other polling data show Trump’s erosion among white women (both college and non-college educated) voters. If we look at the results in Virginia in 2017, we see that Democrats outpaced Hillary Clinton in Washington D.C.’s northern suburbs — home to middle- and upper-middle-class professionals.

It’s easy to see why these voters, formerly comfortable with a Mitt Romney would be alienated from a Trumpized GOP. We think that breaks down into four groups of concerns (each or all four may apply to the newly-aggrieved Republicans).

First, Trump’s ethno-nationalism, which many Republicans were willing to ignore in the campaign, is a mainstay of his agenda — and a turnoff for voters who are comfortable living in a global economy and determined to keep America as an inclusive country.

Second, Trump promised a tougher, more muscular foreign policy than President Barack Obama had. Instead voters see a wild man careening from one needless dust-up with allies to another, trying to undo international agreements seemingly to spite Obama and, worst of all, inviting war with North Korea and coddling Russia. Instead of a sober captain at the ship of state, they have a reckless, unschooled rookie who delights in crashing into the rocks. He is both overly aggressive (threatening war with North Korea) and too docile (e.g., failing to sanction Russia and leaving us open to election meddling).

Third, if the GOP used to be the “Dad” party — sober on the budget, stressing law and order — it’s now a party in the grips of a rule-breaking adolescent with no appreciation for fiscal sobriety. He attacks the FBI, runs up the deficit and enriches himself and his entitled children. When they used to derive a sense of security, managerial expertise and normalcy from Republicans, this guy is making the Democrats look like the fiscally responsible and pro-law enforcement party. Trump brings nonstop chaos, crisis and norm-breaking. For people with organized, stable and rule-compliant lives, this is unacceptable.

Finally, Trump’s treatment of women — and the GOP’s tolerance of him — gnaws at and infuriates women who have previously defended the GOP from the accusation it is conducting a “war on women.” Whereas Democrats saw a party taking away abortion rights, these GOP women felt they were at home and respected in their party. They’ve been swept up in the #MeToo movement as well, whether they don the pink hats or not. Many are just plain angry that someone of Trump’s ilk can boast about assaulting women, defend an accused child molester and defend an accused abuser — and virtually no Republican speaks up to rebuke him. These aren’t women who call themselves “feminists,” but they sure aren’t going to put up with abuse, harassment or veneration of those who abuse and harass. It might not be a particular issue that upsets them, but the party of Trump is now a personal affront to many of these previously GOP women.

So what’s a Democrat to do? Don’t scare them off for one thing. Sound like sober grown-ups. Reject anti-immigrant hysteria on moral grounds as well as economic (we need trade and need immigrants). Remind voters that what makes us American is not race or ethnicity but values and a shared democratic creed. Be tough but sane on foreign policy. Trump has left us with our guard down and saber rattled with no real game-plan for defusing the North Korea crisis. Being clear that Russia poses a threat, our intelligence community is valued and we face a dangerous world where allies are needed will sound reassuring to these ex-GOP voters. And as for women, Democrats should be determined to expose  and end abuse (in the executive or legislative branch, in the military, in business). That means candor, transparency (e.g., hearings) and a clear moral voice.

If Democrats can do these things — promising to end Trump’s abuse of power and the presidency (e.g., conflicts of interest, corruption) with hearings, transparency and accountability — they’ll win over a whole lot of “Republican-leaning independents.” What’s more, they’d lay the groundwork for 2020 when, Democrats better hope, a presidential nominee without Hillary Clinton’s baggage will provide the alternative to the unhinged party of Trump.