When Joe Biden addressed energy during his final debate with Donald Trump he hit a political soft spot that Democrats have long sought — but struggled — to avoid in the resource-rich Southwest: petroleum’s future. While talking about climate change Biden admitted he “would transition away from the oil industry …. which pollutes, significantly.” Trump pounced, eager to weaponize his opponent’s pledge. “Basically what he is saying is he is going to destroy the oil industry. Will you remember that Texas? Pennsylvania? Oklahoma? Ohio?”

While Biden tried to back off his remarks, pledging not to end fracking and not to get “rid of fossil fuels for a long time,” they have forced Democratic candidates in the Southwest into a defensive posture. In Oklahoma, Republican state Sen. Stephanie Bice demanded her Democratic opponent, Rep. Kendra Horn, disavow her party leader. She didn’t have to press much; Horn quickly tweeted her differences with Biden. “We must stand up for our oil and gas industry,” she declared, and, “We need an all-of-the-above energy approach that’s consumer friendly, values energy independence, and protects OK jobs.” Rep. Xochitl Torres Small (D-N.M.) echoed this message, tweeting, “We need to work together to promote responsible energy production and stop climate change, not demonize a single industry.”

Biden’s comments exposed the challenge that has long faced Democrats like Horn and Torres Small in the Southwest. Democrats are trapped between the demands of environmentalists in their party and the economic interests of oil and gas — and the values and ethos these industries have created in the region. Does one protect or puncture the Earth, and at what costs to local community?

This is a stark either-or scenario that politicians and activists have exaggerated over the years, but it is one that has borne real political change, mostly to Democrats’ dismay. In fact, along with civil rights, race and religion, the political economy of oil was a major factor in making the region a Republican stronghold.

Consider the one-party Southwest’s first dalliance with the GOP. Already angered by President Franklin D. Roosevelt’s New Deal regulatory encroachments on oil in the 1930s and 1940s, President Harry Truman enraged Southwest oilmen by taking control of oil leasing in offshore submerged lands. Offshore leasing in the Tidelands (Gulf of Mexico) had become a lucrative venture for states (it funded public schools), and promised to grow even more after oil was discovered there in 1947.

In 1948, the Southwest’s oilmen, like Hugh Cullen, therefore tried to topple Truman. While they remained Democrats, they backed Strom Thurmond’s States’ Rights Democratic Party in an effort to defend segregation (the more familiar part of this story), but also to keep Washington’s hands off the Southwest’s petroleum — something Thurmond promised.

While Truman won, the Tidelands battle raged on.

It reached a crescendo in 1952. Southwestern petroleum kings and political operatives recruited Dwight Eisenhower to the Republican ticket, then backed him with all their resolve. He won, and helped pass the Submerged Lands Act of 1953, which seemed to deliver on the new Republican establishment's promises to let the Southwest’s oil and gas sector run itself.

Cullen signaled the transition, penning a 1952 letter to Sen. Robert Kerr (D-Okla.), urging him to switch allegiances in the face of Democratic-led Washington’s “land grab.” “You are now considering a matter so important that it overshadows national politics, the budget, our international commitments — even the tragedy of Korea …. It is all-important, because if the tidelands are confiscated by the Federal government under the dangerous theory of ‘paramount rights,’ everything will go. If this theory is allowed to stand, there will be no United States as we know it.”

It wasn’t just oil kings who considered the politics of oil pivotal to their decision-making. Kerr also received missives from workers who felt abandoned by a federal government that privileged foreign over domestic oil producers, as well as from locals whose livelihoods demanded his attention. “As I am a royalty owner in Texas County,” one Oklahoma farmer’s wife wrote tersely, “I am writing in regard to the reduction on the Percentage Depletion of the gross income from oil and gas. I DO NOT want it lower than 27½%. Sincerely yours.”

This letter referenced the oil depletion allowance, a “sacred cow” of the tax code that allowed oilmen to deduct 27.5 percent from the gross income they earned from producing wells, along with all the losses from dry holes. While they treasured it, the liberal wing of the Democratic Party saw it as a special interest giveaway. During the 1960 election John F. Kennedy promised to revisit the allowance (foreshadowing a reduction), and only Lyndon Johnson’s presence on the ticket calmed the Southwest’s oilers’ nerves and prevented them from voting Republican across the board.

Their calm was short-lived. By 1962, Kennedy was proposing tax reforms that would include reducing the depletion allowance to 17.5 percent. Kennedy would not see these reforms through, but by the mid-1960s it was apparent to the oil patch’s corporate leaders and citizens alike that a Democratic-led White House was no friend of theirs.

This placed Southwestern Democrats like Robert Kerr in an untenable situation. Party loyalty became harder to justify as Democratic policies targeted his constituents, especially as the environmental movement rose the following decade and became a valued part of the Democratic base.

In the years that followed, with Barry Goldwater’s cowboy conservatism giving way to Richard Nixon’s silent majority and Ronald Reagan’s emphasis on unshackling businesses, the Southwest would undergo what journalist Kirkpatrick Sale deemed a “power shift” in two senses. In the first place, the Southwest was enjoying an unprecedented economic ascent thanks to its riches in oil and gas — homegrown commodities considered valuable as alternatives to foreign crude, the apparent root of the 1970s energy crisis.

In the second, the Southwest was acquiring the cultural power that came with such riches. By the late 1970s, a conservative movement funded by oil bundled the region’s concerns with the right to drill, energy independence, American patriotism, Christian nationalism and throwback family values in one platform, laying the groundwork for a profound political shift.

The GOP finally seized its moment. Democratic politicians of an older generation like Kerr with deep roots and long tenure had survived because they fit the oil patch well. Before Kerr died in 1963, he had walked the line between party and oil politics as an evangelical lay leader, conservationist and an oilman himself who crucially saw his work in oil and politics as a godly vocation, which connected with the region’s self conception. But President Jimmy Carter’s espousal of alternative energy sources and reducing oil consumption forced a breaking point for Democrats a decade later.

In 1980, Carter’s opponent, Ronald Reagan, wooed the Southwestern oil patch with his “Let’s Make America Great Again” platform, which demanded less federal government oversight of the West’s petroleum industry, and a return to the faith values of yesteryear. He highlighted the importance of southwestern oil and gas for American economic and security independence, and christened it an essence of patriotic American religious and political values. Reagan intimated one couldn’t be godly unless they allowed wildcatters to work the land on their terms, without Washington oversight.

Simply by remaining loyal to a party opposed to the economic and spiritual values of the oil patch, someone carved out of Kerr’s mold was betraying not only his constituents, but their core values as well. This message resonated, and made it nearly impossible for Democrats to thread the needle as Kerr once had. By 1980 the choice seemed more stark and simple: protect God’s earthly domain at all cost, or ensure the easy acquisition of its liquid bounty.

Today, as President Trump campaigns with his warning that Joe Biden is “against oil, guns, and God,” the figure of the evangelical oilman and Democratic Sen. Robert Kerr appears to be a relic of the past. Meanwhile the president hopes Biden himself registers among citizens of the oil patch as the Roosevelt and Truman of today, a specter to be feared and opposed in any fossil fuel society.