As the presidential election approaches, American fears of foreign interference are only going to grow. Federal and local officials worry about Russian disinformation campaigns, conspiracy theories and deep fakes amplified by bots and unwitting Americans. The indictments of Lev Parnas and Igor Fruman, both born in the Soviet Union, for allegedly funneling illegal contributions into a Trump-supporting political action committee also amplify fears about the intrusion of dark money into American politics.

Under threat from hackers, misinformation and fake news, it is tempting to view foreign interference as a problem and product of the digital age — aided and abetted by a president who has seemed to welcome it. But foreign meddling in American elections — and international interest in their outcomes — is hardly new, and the past provides lessons on how we can combat the risk.

Throughout the Cold War, the South African government kept a watchful eye on the United States, fearful of American efforts to end its system of legalized white rule. By the beginning of the 1970s, the apartheid government had a severe image problem. The 1960 Sharpeville Massacre had catalyzed the American and European anti-apartheid movements, uniting politicians, activists, trade unionists and students against the apartheid state.

Even more worrying for South African officials, politicians in the United States and Europe increasingly considered levying comprehensive economic sanctions against the apartheid state, designed to coerce racial reform from the unwilling leadership. In 1974, Minister of Information Connie Mulder and his partner, Secretary of Information Eschel Mostert Rhoodie, began appropriating millions from special defense accounts for a “propaganda war in which no rules or regulations count.”

One of their most important tasks: contributing financially to congressional candidates challenging U.S. officials deemed harmful to South Africa’s image. Mulder and Rhoodie funneled money to their preferred candidates through an American public relations firm, Sydney S. Baron & Co. Their first target in 1976: Sen. John Tunney (D-Calif.), who had sponsored legislation cutting U.S. aid to South Africa’s client forces in Angola. His repeated criticism of South Africa’s interference in Angola spurred Rhoodie and Mulder to put $200,000 toward Tunney’s challenger, Republican S.I. Hayakawa. This proved to be a wise investment. Hayakawa defeated Tunney despite the senator’s early lead and incumbency.

Buoyed by this success, the South Africans targeted Sen. Dick Clark (D-Iowa) in 1978. Clark, an ardent critic of South Africa, used his position on the Senate Foreign Relations Committee’s subcommittee on Africa to expose the conditions plaguing black South Africans and to speak out in support of Steve Biko, a South African political prisoner and activist. But it was the Clark Amendment — designed to end American foreign aid for private military forces — that solidified the South African government’s interference. Clark stated openly that “the reason for my amendment was to disassociate us from apartheid and from South Africa.”

Mulder and Rhoodie channeled $250,000 to Clark’s electoral opponent Roger Jepsen, once again through Sydney S. Baron & Co. Legally, Rhoodie, Mulder and Baron & Co. walked a fine line. By contributing to politicians as Sydney S. Baron & Co., the South Africans skirted American campaign finance law. Legally, Baron & Co. had to insist donations came from the firm and not from South Africa because federal law prohibited American companies from serving as conduits for foreign government funds.

Nevertheless, the activities of South Africa’s lobby firms were no secret, and who paid their bills even less so. The Washington Post, the New York Times and the Los Angeles Times, among others, reported on the disturbing activities and donations of various firms on the South African government’s payroll.

The interference against Clark would again prove fruitful. Jepsen — initially lagging behind the high-profile incumbent — undoubtedly benefited from Baron & Co. funds as he struggled to raise money throughout the campaign. At one point, Jepsen possessed a campaign debt of $157,000. Deemed a defender of apartheid by the Des Moines Register, Jepsen ran a vicious campaign attacking Clark on his anti-apartheid activism and his betrayal of American social values — specifically on abortion — which propelled him to a shocking victory.

Simultaneously, Rhoodie and Mulder attempted to introduce a counternarrative about South Africa into the American political discourse by buying space for friendly editorials in newspapers. In these editorials, South Africa’s surrogates stressed the similarities between the United States and South Africa, as two countries mired in “difficult” racial situations. South Africa, the editorials insisted, was a loyal Cold War, anti-Communist partner, holding the line in Southern Africa against the Soviet Union’s designs on the region. Economic sanctions would be a disaster, the editorials claimed, with the apartheid state doing far more for black people than any other African nation.

These editorials appeared in conservative publications like Human Events and National Review, but also in local, less partisan forums like the Seattle Times. Rhoodie even considered more dramatic efforts to introduce a preferable view of South Africa in the U.S. media, including an $11.5 million scheme to buy the Washington Star in 1974. This plot eventually led to the purchase of stock in the Sacramento Union through an American middleman.

After the 1978 revelation of the illegal appropriation of defense funds for Mulder and Rhoodie’s covert campaigns forced the South African prime minister from office and produced additional scrutiny, the propagandists devoted more effort to disguising the South African hand, such as enlisting an even larger network of American academics, foreign policy experts and activists to advocate for South Africa’s preferred policies and candidates. Conservative activists like William Rusher acted as key intermediaries for the South African government, connecting the apartheid state to potential partners in government, private organizations and newspapers.

These efforts intensified from 1984 to 1986, as Congress debated passing comprehensive sanctions against South Africa. The South Africa Foundation sponsored trips and “fact-finding missions” for Americans to travel to the apartheid state and report back to the American public. The Rev. Jerry Falwell took the most infamous of these trips in April 1985. During the “mission,” Falwell called the beloved anti-apartheid activist Bishop Desmond M. Tutu a phony with no authority to speak for black people on apartheid.

These efforts fueled rampant misinformation surrounding the extent of the South African government’s reforms, vile conspiracy theories about Nelson and Winnie Mandela and intense attacks on Americans leading the sanctions effort, including Sen. Richard Lugar (R-Ind.).

Critically, this misinformation effort asserted throughout the 1980s that black workers would be the “first victims” of sanctions. The South African government and its surrogates commissioned dozens of economic studies “proving” the “irreparable” damage of sanctions to black South Africans. This push included moderate black leaders like Chief Mangosuthu Buthelezi and Bishop Isaac Mokoena traveling to the United States to argue that sanctions were deeply unpopular among black South Africans.

These arguments gave President Ronald Reagan the grounds to veto a sanctions bill in 1986.

But despite the best efforts of the South African government, Congress overrode President Ronald Reagan’s veto, a rare congressional rebuke of presidential foreign policy. Disinvestment proved popular with Americans, foreign audiences and most importantly, among many South African liberation movements like Nelson Mandela’s African National Congress.

But while the apartheid government ultimately failed to forestall harsh economic sanctions, its interference efforts took root in the United States because Americans proved all too willing to support its interference in U.S. affairs. Some were motivated by ideology — stalwart in their support of an anti-communist partner — some by racism, horrified at the prospect of losing the last system of legalized white rule, and some by pure profit, willing to support whomever to secure funding and notoriety. The South Africa case offers a cautionary tale to Americans — foreign interference does not always rely on high-tech schemes. Sometimes you just need a few ready partners.

As Americans approach November worrying about foreign interference, they should remember that it cannot succeed without willing Americans. Americans can and must safeguard their own elections, and those who refuse — and stand to benefit from interference — must be called out for their actions.