A long time ago, in a galaxy far, far away, I was an elected Republican Party official. Actually, it was in Cuyahoga County, Ohio, in the early 1980s. But it might as well have been in a time and place that is now a distant legend — not because I am so different, but because the Republican Party I was glad to support in those days has become unrecognizable.

As a teenager I gravitated to the GOP because by instinct I was conservative. In college, the more I learned about political ideas, the more comfortable I felt in the Republican big tent. Even before I was old enough to vote, I was active in my local chapters of College Republicans and Young Americans for Freedom. The first time I cast a ballot for president was in 1980. I cast it unhesitatingly for Ronald Reagan, who embodied the American conservatism I found so appealing.

By that point I was a law student in Boston, and conservative Republicans were a decided minority on campus. But Reagan carried Massachusetts that year and went on to become a popular and effective president. To my mind, the conservative Republican outlook he and other GOP leaders embraced seemed self-evidently correct. The party was often analogized to a three-legged policy stool: It fused together voters who wanted to advance (1) market economics, (2) national security, and (3) social conservatism. Resisting communism, expanding individual freedom, and reducing the size of government were part of the formula too. That worldview made good sense to me. By and large, it still does.

After earning my law degree, I moved to Cleveland to work for a large law firm. I don’t recall how I first got in touch with the local GOP, but at some point I was asked to run for precinct committeeman in my town — the lowest rung on the Republican hierarchy. Intrigued by the idea, I agreed. It wasn’t a contested election, so voting for myself was all it took to “win.” That was the beginning and end of my involvement in Ohio Republican politics: A few months later I left the law firm and returned to Boston, where I went to work for Ray Shamie’s US Senate campaign. That was in 1984. I’ve been here ever since.

Shamie didn’t win that election. But he later became chairman of the shambolic Massachusetts Republican Party and set about rebuilding it into a meaningful political operation. By 1990, he had succeeded. Bay State voters that year elected a Republican governor, lieutenant governor, and treasurer, and sent 16 Republicans to the state senate. Two years later, two Republican congressmen were elected as well.

Very gradually, though, the Reaganesque style of Republicanism represented by Shamie was losing its appeal. In 1992, Patrick Buchanan — an intolerant hard-right culture warrior — mounted a challenge to then-president George H.W. Bush. His signature issues were a far cry from those Reagan (and Shamie) had championed. Buchanan demanded a crackdown on immigration, nonintervention in foreign affairs, and stiff barriers against free trade. It sounded like a throwback to the blinkered isolationists of the 1930s, and I was dismayed to see that some Republicans liked it. When Buchanan ran again for the GOP nomination in 1996, I wrote a column arguing that he represented the opposite of everything Republicans were supposed to favor.

“He talks envy, not growth; acrimony, not optimism,” I insisted. “His signature proposals on immigration and trade would make government bigger and taxes higher. Wafting through the Buchanan message is the whiff of authoritarianism, not the breeze of freedom… . It’s conservatism of the hardened heart.”

Nevertheless, Buchanan won the primaries in New Hampshire and three other states. His campaigns didn’t succeed, but his message was winning adherents. A rough beast was slouching toward Bethlehem to be born. It was unnamed then, but today we know it as MAGA.

Not long after taking my first newspaper job (I joined the Boston Herald in 1987 and moved to the Globe in 1994), I changed my party registration from Republican to independent. Originally I did so as a gesture of impartiality. But as the Republican Party acquired more and more of the Buchananite sourness, I stopped thinking of myself even as “Republican-leaning.” More and more often I began to clarify that I was not a Republican but a conservative — specifically, a Reagan conservative. I found myself increasingly unwilling to vote for Republicans who stood for policies and values that, to my mind, were the antithesis of sound conservatism.

Especially odious to me was the rising tide of nativism in the GOP. Mitt Romney, for example, used to support a sensible path to legalization for most undocumented immigrants. But as a candidate for president, he reversed himself, boasting of all the ways he had cracked down on illegal migrants and vowing to pressure them into “self-deportation.”

Romney similarly recast himself as a protectionist, pledging to raise tariffs and not let “the Chinese … take by trade surrender what we fear to lose in a trade war.” Romney is just one example of how, even before Donald Trump appeared on the stage, leading Republicans were already turning their backs on values that had once gone to the very essence of Republican thinking.

Today, roughly half of all US voters say they identify with no political party — and their number has been growing steadily.

Once Trump did emerge, it was to bury whatever remained of the GOP’s attachment to the ideals of the party I once belonged to. I had been repelled by the way Democrats circled the wagons around Bill Clinton, whose dishonesty and low character I thought should be disqualifying. To my disgust, Republicans began doing the same for Trump even before he got elected. More than was ever the case with Clinton or any previous president, Republicans have remade their party into a cult of personality. In today’s GOP, Trump is everything. Virtually no leading party members will openly oppose him on anything. Indeed, much of the party’s rank and file appears to revel in his boorish and insulting narcissism. And almost nothing that Trump stands for now bears any connection to the “three-legged stool” that once made the Republican Party so successful.

Like millions of Americans, I find myself politically homeless today. Neither major party offers a vision I can relate to. I am as turned off by the Democrats’ toxic obsession with race and gender as I am by the Republicans’ shrillness on immigration. I fear the threat posed by the Democratic left to freedom of speech and conscience and am alarmed by the Republican right’s antipathy to maintaining US leadership in world affairs.

In 2016, I thought the Republican Party was headed for a crack-up, much as the Whig Party collapsed in the 1850s. I am alienated from both of America’s two major parties. In the last two presidential elections, I voted for the Libertarian ticket and imagine I will vote for a third-party ticket again this year. In state elections, I am usually stymied. The Massachusetts Republican Party occasionally nominates challengers to the Democrats who hold nearly every public office, but with very rare exceptions, all of them now are lockstep Trumpian loyalists.

Today, half of all US voters say they identify with no political party, and their number has been rising steeply. When push comes to shove, most ballots are still cast for Republicans and Democrats. At some point there must be a limit to the level of disillusionment that America’s two-party tradition can withstand. When that point is reached, then what? Will an unprecedented wave of independent candidates make it onto the ballot at last, propelled by voter desperation for new choices? Will one — or both! — of the major parties be captivated by a transformative new leader? Will a third party at last succeed in breaking the two-party duopoly that has for so long bestrode American politics like a colossus?

America didn’t end when the Federalist Party disintegrated or when the Whigs finally breathed their last. The nation moved on to something better. If enough of us refuse to give our votes to any candidates with a D or an R after their name, there is no reason it cannot do so again.