‘The whole secret of politics is knowing who hates who,” Kevin Phillips told the journalist Garry Wills during the 1968 US presidential campaign. Phillips, who has died aged 82, was the political analyst behind Richard Nixon’s “southern strategy”, aimed at exploiting racial tensions to draw to the Republican side the more conservative voters in the south, where the Democrats had dominated since the American civil war primarily because Abraham Lincoln had been a Republican. Although both he and Nixon later played down his direct influence, Phillips’ keen perception of the changing antipathies of the American electorate, detailed in his 1969 book The Emerging Republican Majority, lay at the heart of Nixon’s victory. Phillips’s analysis was not limited to the south. He realised that traditional working-class Democrats were becoming alienated not just by the party’s embrace of civil rights, but were also sympathetic to conservative positions against the Vietnam war, protest, federal spending and the 1960s “cultural revolution”. Though he predicted their drift rightward to the Republicans, he could not foresee the long-term effect of this political tsunami, stoked by culture wars, and he eventually disavowed the division his work had sowed, becoming, by the George W Bush presidency, a leading voice of apostate Republicanism. Phillips’ analysis echoed a century of US political history. After John F Kennedy’s assassination, Lyndon Johnson pushed the Civil Rights Act (1964) and Voting Rights Act (1965) through Congress. Johnson was a master of political compromise, but when he signed the latter bill, he supposedly told an aide, “there goes the south”. The so-called “solid south” always voted Democrat, but these naturally conservative “Dixiecrats” were at odds with the rest of their party, which primarily represented working people in the north. Similarly, the Republicans were traditionally a party of big business, led by industrial magnates whose sense of noblesse oblige rendered them relatively liberal on social issues. But they also harboured a fierce right wing committed to undoing Franklin Roosevelt’s New Deal and opposed to any hint of government regulation. These factional divisions facilitated legislative compromise, but Johnson’s prediction soon proved true, as Dixiecrats deserted to the Republicans. Starting with Nixon’s re-election in 1972, Republicans swept the south five times in nine presidential elections, stymied only by the southerners Jimmy Carter and Bill Clinton. Phillips was born in New York City, where his father, William, was chairman of the New York State Liquor Authority, and his mother, Dorothy (nee Price), was a homemaker. He graduated from Bronx high school of science at 16, by which time he had already begun studying the political makeup of his city, discerning an antagonism towards the black and Hispanic community by the white working-class children of an older generation of immigrants. Already a loyal Republican, after graduation he headed the Bronx’s youth committee supporting the re-election of Dwight D Eisenhower. He earned his BA in political science from Colgate University in 1961, having spent a year at Edinburgh University studying economic history, and took a law degree from Harvard in 1964. His political career began as an aide to the Republican congressman Paul Fino, from the Bronx, where he realised that despite Fino’s relatively liberal domestic positions Republicans could not depend on minority voters. Phillips lent his prodigious research into the breakdown of the nation’s congressional districts to the Nixon campaign, and after the election he became a special assistant to the attorney general John Mitchell, Nixon’s campaign manager, who would be jailed in the fallout from the Watergate scandal. He left Mitchell in 1970, becoming a commentator, with a syndicated newspaper column, his own newsletter and regular appearances as a broadcasting pundit. Phillips later traced Republican failures back to Watergate, although ironically it was his tip to the Nixon aide Jeb Magruder about the damaging information that might be in the Democratic party chairman Larry O’Brien’s Watergate office that precipitated the fatal burglary. Phillips coined the terms “sun belt” for the fast-growing areas of the southern and south-western states, and “new right” to distinguish the populist politics of Ronald Reagan from those of “elitists” such as Nelson Rockefeller. But as the white working-class shrank, along with its jobs, the politics of resentment grew more divisive. Dog-whistles to racists, from Reagan’s “welfare queens” to George HW Bush’s Willie Horton ads portraying a black murderer, culminated in the 1994 “Republican revolution” which captured Congress and proceeded to shut down the government. What Phillips had not foreseen was the impossibility of political compromise now that all the different reactionaries were in the same Republican boat. Watching the growing economic inequality which sprang from the Reagan years, he began to have second thoughts. His belief in his party as a stable, serious preserver of the status quo began to fall apart. Starting with Wealth and Democracy (2002), Phillips produced a series of books excoriating what he saw as George W Bush’s plutocratic revolution, recalling the robber barons of the 19th-century Gilded Age. He warned of an instinct toward authoritarianism under the guise of fighting so-called liberal permissiveness. Phillips castigated the Bushes further in American Dynasty (2004) for aiding already rich investors, especially in the sun belt’s energy and defence industries, at the whim of the Pentagon and CIA. American Theocracy (2006) recognised the growing influence of fundamentalist Christians in the Republican party, a dystopian vision of ideological extremism mixed with greed-driven fiscal irresponsibility. His 2008 book Bad Money focused on what he called “bad capitalism”, relying on financial services instead of industrial production. After the 2008 financial crash, he wrote a sequel, After The Fall (2009). By now he was a regular in such centrist outlets as National Public Radio or the Atlantic, where he found himself explaining how his analysis of the changing American electorate led, with some inevitability, to the polarised society that elected the authoritarian Donald Trump. Among his 15 books, Phillips also produced a biography of the US president William McKinley (2003) and 1775: A Good Year for Revolution (2012), about the circumstances which precipitated that war. He is survived by his wife, Martha (nee Henderson), whom he married in 1968, and their three children, Betsy, Andrew and Alec. Kevin Phillips, writer and political commentator, born 30 November 1940; died 9 October 2023