at the upcoming primary election: By 1910, the political supporters of the Mississippi Democratic Party politician James K. Vardaman—chiefly poor white farmers—began to describe themselves proudly as "rednecks", even to the point of wearing red neckerchiefs to political rallies and picnics. Linguist Sterling Eisiminger, based on the testimony of informants from the Southern United States, speculated that the prevalence of pellagra in the region during the Great Depression may have contributed to the rise in popularity of the term; red, inflamed skin is one of the first symptoms of that disorder to appear. Coal miners The term "redneck" in the early 20th century was occasionally used in reference to American coal miner union members who wore red bandanas for solidarity. The sense of "a union man" dates at least to the 1910s and was especially popular during the 1920s and 1930s in the coal-producing regions of West Virginia, Kentucky, and Pennsylvania. It was also used by union strikers to describe poor white strikebreakers. Late 20th and early 21st centuries Writers Edward Abbey and Dave Foreman also use "redneck" as a political call to mobilize poor rural white Southerners. "In Defense of the Redneck" was a popular essay by Ed Abbey. One popular early Earth First! bumper sticker was "Rednecks for Wilderness". Murray Bookchin, an urban leftist and social ecologist, objected strongly to Earth First!'s use of the term as "at the very least, insensitive". However, many Southerners have proudly embraced the term as a self-identifier. Similarly to Earth First!'s use, the self-described "anti-racist, pro-gun, pro-labor" group Redneck Revolt have used the term to signal its roots in the rural white working-class and celebration of what member Max Neely described as "redneck culture". As political epithet According to Chapman and Kipfer in their "Dictionary of American Slang", by 1975 the term had expanded in meaning beyond the poor Southerner to refer to "a bigoted and conventional person, a loutish ultra-conservative". For example, in 1960 John Bartlow Martin expressed Senator John F. Kennedy should not enter the Indiana Democratic presidential primary because the state was "redneck conservative country". Indiana, he told Kennedy, was a state "suspicious of foreign entanglements, conservative in fiscal policy, and with a strong overlay of Southern segregationist sentiment". Writer William Safire observes it is often used to attack white Southern conservatives, and more broadly to degrade working class and rural whites that are perceived by urban progressives to