Between the orbits of Mars and Jupiter lies the asteroid belt, which consists of the pieces of a potential planet that never formed because gravitational forces tore its components apart. What remains are chunks of rock and metal that occasionally flame out in the earth’s atmosphere as falling stars.

In Rule and Ruin: The Downfall of Moderation and the Destruction of theRepublican Party, Geoffrey Kabaservice provides a sort of natural history of a missing political planet. The author of a well-received biography of Yale president Kingman Brewster, The Guardians: Kingman Brewster, His Circle, and the Rise of the Liberal Establishment, Kabaservice provides a thorough and entertaining account of the decline of the moderate wing of the Republican Party and the Northeastern establishment with which its membership overlapped.

The last half of the 20th century has been presented as a series of triumphs against great odds by the conservatives who captured and now dominate the Republican Party.

Winners write the history, and the last half of the 20th century has been presented as a series of triumphs against great odds by the conservatives who captured and now dominate the GOP, from the founding of National Review in 1955 by William F. Buckley, Jr., to the 1964 convention that nominated Barry Goldwater for president and featured “The Speech” by Ronald Reagan that propelled him to the governor’s office in California and then to the White House in 1981. Kabaservice gives us the history of the conservative coup from the side of the losers, many of whose names would be recognized only by the oldest readers—“men such as Lindsay, Percy, Hatfield, and Goodel.” In the 1960s and1970s, centrist Republicans sought to counter the influence of conservative journals like National Review and Human Events with Advance and the Ripon Forum, the journal of the Ripon Society, a would-be counterweight to the militant right.

From his archaeological work, Kabaservice sometimes returns with interesting relics, including a widely-read 1970 essay by Harvard graduate student and Ripon Society president Lee Auspitz entitled “For a Moderate Majority” and published in, of all places, Playboy. Auspitz denounced Richard Nixon’s attempt to create “a permanent majority” by means of deliberate polarization: “Those who are left out of such a majority become alienated and radicalized … The permanent majority reacts by repressing the minority; but to do so effectively, it must adopt measures that restrict the liberty of all citizens.”

Nixon himself was a transitional figure, who played off the new right against the old establishment. Although Nixon was moderate compared to Reagan, who in turn was moderate compared to the contemporary Republican leaders who invoke his name, Kabaservice views Nixon as the architect of conservative populism, which resonated with the middle-class Californian’s reciprocated loathing of eastern elites. According to Kabaservice, Nixon believed (and said) that, “The American upper class now has become like the British upper class,or much worse, I should say like the French upper class was before WorldWar II: decadent, incestuous, homosexual.”

From the 1960s onward, the history of the moderate Republicans, like that of the Ottoman Empire, is largely one of decline. Moderate Republican John Anderson, unable to stomach his party’s nomination of Reagan, ran as an independent for president in 1980, and in the same decade a group of Northern moderates formed their own “Gypsy Moth” coalition to counteract the influence in Congress of conservative Southern Democratic “Boll Weevils.” But the inexorable trajectory of the Republican Party was southward in geography and downward in socio-economic class.

“To some extent, the moderates’ downfall was caused by forces beyond their control,” Kabaservice notes. “These included the shift of population and power from the North and Midwest to the South and West, the declining cultural sway of the eastern WASP establishment and its ethos, and the waning public memory of the Depression and World War II.”

Motivated by opportunism or sincere conversion, some leading moderate Republicans threw in their lot with the ascendant right. In 1972, George Gilder, the editor of the Ripon Forum, published an editorial, later expanded into the book Sexual Suicide, in which he blamed the welfare state for family disintegration. He later became a cheerleader for supply-side economics. Chrisopher DeMuth moved from working on the campaign of James Farmer, a black Republican who co-founded the Congress of Racial Equality (CORE) to the presidency of the right-wing American Enterprise Institute. Another former moderate was Donald Rumsfeld: “Rumsfeld’s best friend in Congress had been Allard Lowenstein, a leader in the antiwar movement and one of the most liberal Democrats in Congress, whom he had met when they both worked as Congressional aides in the late 1950s.” The two were fond of “wrestling in the House gym and debating political philosophy late into the night.”

While moderates have been reduced in status, their ideas have had more influence than Kabaservice acknowledges, particularly among today’s Democrats, whose core territory is now the Northeast and Pacific Coast. BarackObama has sometimes been described as an Eisenhower Republican, and indeed he has less in common with New Deal liberals like FDR and LBJ than with the old Eisenhower and Rockefeller Republicans, in matters that range from a cautious foreign policy to a willingness to cut Social Security and Medicare in the name of fiscal conservatism.

Planet Moderate has disintegrated, but the gravitational influence of its debris continues to be felt.

Michael Lind is co-founder of the New America Foundation and author of Land of Promise: An Economic History of the United States.