Finley Peter Dunne, writing in the Irish dialect of a mythical Mr. Dooley, was the shrewdest observer of early 20th-century politics. One of his most lasting observations (up there with “Politics ain’t beanbag”) was “Th’ Supreme Coort follows th’ election returns.”

Leaving legal arguments aside, Monday’s 6-to-3 Supreme Court decision outlawing job discrimination based on sexual orientation and gender identity (with Trump appointee Neil Gorsuch writing for the majority) certainly follows public opinion. A mid-2019 Gallup poll found that a whopping 93 percent of Americans believed “gays or lesbians should … have equal rights as non-gays or non-lesbians in terms of job opportunities.”

Social change is rarely that dramatic. It was just eight years ago that Joe Biden got ahead of most Democrats, including Barack Obama, by endorsing gay marriage on “Meet the Press.” And it was five years ago this month that the Supreme Court made gay marriage the law of the land in a narrow 5-to-4 decision.

But there still are holdouts, as first-term Virginia GOP Rep. Denver Riggleman learned to his dismay over the weekend.

Partly because Riggleman had officiated at a gay marriage, he was denied renomination to Congress. Admittedly, it is hard to draw epic conclusions from the results of a single party convention held in a church parking lot in the middle of a pandemic. But Riggleman’s defeat is a reminder that even voting the pure Trump line in Congress is no guarantee of a secure future in today’s Republican Party.

But this is also a moment to marvel at the speed of social change in 21st-century America. A quarter-century ago, as politicians in both parties catered to “law and order” fears, it would have been difficult to imagine a national uprising against police violence, especially shootings of African Americans and other minorities.

Donald Trump, the ultimate blast-from-the-past politician, tweeted Saturday, “LAW & ORDER.” The screaming capital letters can be seen as a wail that fear-mongering built around crime no longer seems to be working as a political tactic.

Officeholders in both parties live in mortal terror of attack ads. For decades, legislators who should have known better voted for draconian laws for fear of being labeled “soft on crime.”

Among white politicians, only the most unrealistic bleeding hearts have pointed with shame to the reality that America rivals China for the world’s largest prison population. We all know — from movies, if not real life — the horrors of prison conditions, yet we collectively have turned a blind eye.

Maybe the message of the moment — one that goes far beyond the tragedy of George Floyd — is that the old attack lines no longer work. Maybe it will be possible in Congress and the states to smartly legislate on crime and prisons without fear of retribution at the ballot box.

Political epithets, even the most powerful ones, have a shelf life. Take “socialized medicine.”

From the 1940s, when Harry Truman proposed a national health insurance plan, to the 1960s, when the American Medical Association waged a scorched-earth battle against Medicare, opposition to socialized medicine was a conservative rallying cry. But by the mid-1970s, most newspaper mentions of socialized medicine referred to the British health care system.

We may have reached that point with the holy grail of a balanced budget.

In 2010, Obama appointed a commission led by former GOP Sen. Alan Simpson and former Bill Clinton chief of staff Erskine Bowles to explore deficit reduction. The resulting Simpson-Bowles plan, released under a Democratic president, called for adjustments in both Social Security and Medicare to reduce future costs.

What a difference a decade makes.

Long before the pandemic and the resulting economic collapse, conservatives had abandoned any semblance of fiscal restraint. Powered by the Trump tax cuts that were cheered on by a united Republican Party, the federal deficit hit the $1 trillion mark in calendar year 2019.

Given that track record (and remember, this was before COVID-19), it is nearly impossible for Republicans to emulate Ronald Reagan and lambaste their opponents as “tax and spend liberals.” And if GOP candidates try such retro rhetoric in speeches or TV ads, they should be prepared for voters to shrug their shoulders in confusion.

No one planned it like this. But we are at a moment — partly brought on by a horrendous virus and out-of-control local police departments — when most of the traditional certainties of American politics are fast vanishing.

Based on current reelection polls, Trump seems more the dying gasp of the old country club America than the avatar of a new ethos built around economic nationalism and do-it-my-way authoritarianism. In these last weeks, Trump has met the future — and discovered that it doesn’t want any part of him.

With more than 110,000 dead from COVID-19 and unemployment at Depression levels, I worry about seeming too hopeful about the future.

But I can’t help thinking about the George Bernard Shaw line that Robert Kennedy rewrote a bit during his foreshortened 1968 presidential campaign.

Kennedy would end his speeches with these words: “Some men see things as they are and say, ‘Why?’ I dream things that never were and say, ‘Why not?’”

Amid the heartbreak and the turmoil of the moment, perhaps we have reached a rare “Why not?” moment in American history. How I hope that’s true.

Walter Shapiro has covered the last 10 presidential campaigns. He is also a fellow at the Brennan Center for Justice at NYU and a lecturer in political science at Yale. Follow him on Twitter @MrWalterShapiro.