On Tuesday, as Republicans in the US House of Representatives convulse over electing one among them as speaker of the House, with Kevin McCarthy attempting to outmanoeuvre his hardcore Maga detractors, the civil war in the Republican party comes into the open.

But it’s not particularly civil and it’s not exactly a war. It’s the mindless hostility of a political party that’s lost any legitimate reason for being.

For all practical purposes, the Republican party is over.

A half century ago, the Republican party stood for limited government. Its position was not always coherent or logical (it overlooked corporate power and resisted civil rights), but at least had a certain consistency: the party could always be relied on to seek lower taxes and oppose Democratic attempts to enlarge the scope of federal power.

This was, and still is, the position of the establishment Republican party of the two George Bushes, of its wealthy libertarian funders and of its Davos-jetting corporate executive donor base. But it has little to do with the real Republican party of today.

In the 1990s, Newt Gingrich and Fox News’s Roger Ailes ushered the Republican party into cultural conservatism – against abortion, contraception, immigration, voting rights, gay marriage, LBGTQ+ rights, and, eventually, against transgender rights, teaching America’s history of racism and, during the pandemic, even against masks.

At the same time, cultural conservatism was for police cracking down on crime (especially committed by Black people), teaching religion with public money, retailers discriminating against LBGTQ+ people, and immigration authorities hunting down and deporting undocumented residents.

Gingrich and Ailes smelled the redolent possibilities of cultural conservatism, sensed the power of evangelicals and the anger of rural white America, saw votes in a Republican base that hewed to “traditional values” and, of course, racism.

But this cultural conservatism was inconsistent with limited government – in effect, it called on the government to intrude in some of the most intimate aspects of personal life.

The party line became confused, its message garbled, its purpose unclear. It thereby created an opening for a third and far angrier phase, centering on resentment and authoritarianism.

The foundation for this third phase had been laid for decades as white Americans without college degrees, mostly hourly-wage workers, experienced a steady drop in income and security.

Not only had upward mobility been blocked, but about half their children wouldn’t live as well as they lived. The middle class was shrinking. Well-paid union jobs were disappearing.

Enter Donald Trump, the con artist with a monstrous talent for exploiting resentment in service of his ego.

Trump turned the Republican party into a white working-class cauldron of bitterness, xenophobia, racism, anti-intellectualism and anti-science paranoia, while turning himself into the leader of a near religious cult bent on destroying anything in his way – including American democracy.

A political party is nothing more than a shell – fundraising machinery, state and local apparatus and elected officials, along with a dedicated base of volunteers and activists. The base fuels a party, giving it purpose and meaning.

Today’s Republican base is fueling hate. It is the epicenter of an emerging anti-democracy movement.

What we are seeing played out today in the contest for the speakership of the House involves all of these phases – what remains of the small-government establishment, the cultural warriors and the hate-filled authoritarians – engaged in hopeless, hapless combat with each other.

They are also in combat with the aspirations and ideals of the rest of America.

The Republican party will continue in some form. It takes more than nihilistic mindlessness to destroy a party in a winner-take-all system such as we have in the United States.

But the Republican party no longer has a legitimate role to play in our system of self-government. It is over.

• Robert Reich, a former US secretary of labor, is professor of public policy at the University of California, Berkeley, and the author of Saving Capitalism: For the Many, Not the Few and The Common Good. His new book, The System: Who Rigged It, How We Fix It, is out now. He is a Guardian US columnist. His newsletter is at robertreich.substack.com