Josh Zeitz has taught American history and politics at Cambridge University and Princeton University and is the author of Lincoln’s Boys: John Hay, John Nicolay, and the War for Lincoln's Image. He is currently writing a book on the making of Lyndon Johnson’s Great Society. Follow him @joshuamzeitz.

Something quite remarkable happened this morning. Donald J. Trump, the Republican nominee for president, beseeched the government of Russia, a foreign and quasi-hostile country, to hack the private email account of Hillary Clinton, his Democratic opponent. “Russia, if you’re listening, I hope you’re able to find the 30,000 emails that are missing,” he told a room of flummoxed reporters. “I think you will probably be rewarded mightily by our press.”

For those few readers who aren’t up to speed, let’s back up a step. It appears increasingly likely that a Russian state intelligence agency illegally accessed the Democratic National Committee’s internal servers and enlisted WikiLeaks to publicize damaging internal emails on the eve of the Democratic convention. Most observers believe that Russia’s government initiated this criminal act in the service of tilting the presidential election to Trump, who proposes to take the United States out of NATO and whose personal financial ties (and potential dependency) on Russian investors raise a host of troubling questions.


In fact, this is not the first time that a Republican nominee has benefited from foreign interference in an American presidential election. The year was 1968, the candidate was Richard Nixon and the country was South Vietnam.

***

In the fall of 1968, Vice President Hubert Humphrey, the Democratic presidential nominee, found himself trailing his Republican opponent Richard Nixon by a consistent and seemingly insurmountable gap in the polls. Bleeding the support of conservative Democrats, who gravitated to George Wallace’s third-party candidacy, he also faced trouble on his left flank. Unable to disassociate himself from President Lyndon Johnson’s deeply unpopular war policy in Vietnam, he became an uncomfortable proxy for the White House. Wherever he went, anti-war protesters heckled him, shouting “Stop the War, “Seig Heil,” and “Shame, Shame.”

It hardly mattered that Richard Nixon’s position on Vietnam was totally indiscernible. Though he had told a New Hampshire audience, “Yes, I have a plan to end the war,” and though he promised that he would “end the war and win the peace in the Pacific,” Nixon stubbornly refused to reveal even the scantest details of his “plan,” which, to his chagrin, reporters took to calling a “secret plan.” “I don’t want to pull the rug out from under our negotiations in Paris” by giving away too much detail, he explained. Unlike Humphrey, he could afford to be vague. He was not a member of the current government and stood for change, ipso facto.

With his campaign in shambles, Humphrey’s only hope was to break with Johnson and reverse course on Vietnam. On September 30, he did just that, announcing that upon taking office he would unilaterally halt the bombing of North Vietnamese targets and thus take a “risk for peace.”

As organized labor mobilized to stem the flow of working-class defections to Wallace, and as peace Democrats moved into Humphrey’s column, Nixon’s lead shrunk to five percentage points by October 20. Then, on October 30, Nixon’s advantage all but vanished as Johnson sprung an “October surprise,” announcing to a prime-time television audience that North Vietnam and its ally, the National Liberation Front, had agreed to a new round of four-way peace talks with the United States and its ally, the Saigon-based Government of Vietnam (GVN). Johnson also told the nation that Hanoi had agreed to stop bombing South Vietnamese cities in return for a halt in America’s bombing campaign north of the demilitarized zone. With hopes for peace running high, Humphrey surged in the polls, leading Nixon by three points on November 2.

But Nixon had an October surprise of his own. In the three weeks leading up to the election, as a newly invigorated Hubert Humphrey barnstormed the nation, touting a platform of “human equality and human opportunity,” crying out for “a spirit of community,” visiting black churches and tearfully celebrating America, “the only country on the face of the earth that has ever dared to try to make what we call a biracial, pluralistic society work,” Nixon’s campaign was using back channels to scuttle the Johnson administration’s negotiations with the various parties in Vietnam.

Nixon’s team met secretly with Anna Chan Chennault, a wealthy supporter of Taiwanese President Chiang Kai-shek, co-chair of Republican Women for Nixon and confidante of South Vietnamese President Nguyen Van Thieu. At Nixon’s behest, Chennault informed Thieu that Nixon would secure a better deal for his country than either Humphrey or Johnson, and that the Democrats were effectively prepared to sell out Saigon in order to secure peace at any price. If Chennault could convince Thieu to stay away from the negotiating table, the talks would collapse, LBJ would look foolish and the Democrats’ 11th-hour gambit would fail.

Incredibly, Lyndon Johnson and Hubert Humphrey knew of Nixon’s maneuvers. The National Security Agency intercepted cables between Thieu and his ambassador in Washington, D.C. (“[I am] still in contact with the Nixon entourage, which continues to be the favorite despite the uncertainty provoked by the news of an imminent bombing halt,” one communiqué began.) On the basis of these cables, LBJ ordered the FBI to tap Chennault’s phone; the bureau, in turn, concluded that she “contacted Vietnamese Ambassador Bui Diem and advised him that she had received a message from her boss (not further identified) which her boss wanted her to give personally to the ambassador. She said the message was that the ambassador is to ‘hold on, we are gonna win’ and that her boss also said, ‘Hold on, he understands all of it.’”

Johnson was furious. He regarded Nixon’s willful interference as “treason” (and, indeed, it appeared to be a gross violation of the Logan Act, which prohibits individuals from negotiating with foreign governments. Yet he and Humphrey agreed not to go public. They lacked a definitive “smoking gun” that tied Nixon to the arrangement, and they were loath to compromise American intelligence services by acknowledging the taps and intercepts.

In the end, Nixon’s October surprise trumped LBJ’s. On November 2, Thieu announced that “the government of South Vietnam deeply regrets not being able to participate in the [peace] talks,” and as quickly as it had emerged, the euphoria over LBJ’s October 31 announcement broke. Without South Vietnamese participation in the Paris talks, there was little chance of final resolution.

It’s impossible to say whether Nixon’s October surprise was decisive. The election results were painfully close, with Nixon taking 43.4 percent of the popular vote to 42.7 percent for Humphrey and 13.5 percent for Wallace. But it’s eminently plausible that a dramatic diplomatic breakthrough might have swung the map to Humphrey.

It wouldn’t be the last time that Nixon violated the law to win a presidential election. Neither would it be the last time that a foreign power intervened in an American presidential election.

***

On November 4, 1979, roughly 3,000 Iranian university students stormed the U.S. embassy in Tehran and took 63 American diplomats and servicemen hostage.

It was all precipitated by a dramatic regime change in the Islamic state. Since 1953, when the CIA helped coordinate the overthrow of nationalist Prime Minister Muhammad Mossadegh in an effort to safeguard western oil concerns in the region, the American government had provided generous economic and military assistance to Mohammad Reza Pahlavi, the shah of Iran. A secularist who strove to modernize his country, the shah was also a corrupt authoritarian who embezzled billions of dollars in public funds and employed brute force against his political opponents.

When a loose coalition of Muslim fundamentalists, middle-class reformers and military dissidents finally toppled his regime in February 1979, the U.S. government faced a difficult decision: It could either cooperate with the new head of the Islamic state— Ayatollah Sayyid Ruhulla Musawi Khomeini, an Islamic fundamentalist who harbored a strong anti-American bias—or keep its distance. Declining to use military force to help restore the shah to power, the Carter administration also allowed the exiled shah to enter the United States in late 1979 to seek cancer treatment. When Carter refused the ayatollah’s demands that the shah be returned to Iran to face trial, and that his personal wealth be turned over to the state, student radicals in Tehran decided to strike back at the “Great Satan.”

The hostage crisis proved a weight around President Jimmy Carter’s neck. Throughout the fall of 1980, Carter’s team had hoped against hope for a resolution to the standoff. For a time, it seemed possible that Iran might release the hostages before the election. They had had served their purpose from a propaganda standpoint and were becoming an unnecessary burden to the Islamic government in Tehran. With Iran now locked in a costly war with its neighbor, Iraq, and with the shah dead of cancer, the ayatollah was eager to unfreeze his country’s foreign-held assets. Ronald Reagan’s advisers were also well aware that negotiations between Iran and the United States were nearing a successful resolution. But Reagan also understood that Iran might hold the key to the election—so much so that he deployed his running mate, George H. W. Bush, former President Gerald Ford, and Henry Kissinger to decry foreign “manipulation” of an American election.

He needn’t have worried. If Tehran was tipping the scale, it wasn’t for Jimmy Carter, whom the ayatollah despised—in part for his decision to admit the shah for treatment, and because Carter ordered a military rescue operation (albeit, a badly bungled one). After stalling long enough to see the incumbent president vanquished at the polls, the ayatollah then waited quite literally until the moment he left office before releasing the American captives. Experts then and since agree that the timing could not have been coincidental.

For many years, there were persistent whispers in the Beltway that Reagan's campaign manager, William Casey, who later became CIA director, colluded with persons close to the ayatollah to delay the release of the hostages. But there is no compelling evidence to suggest this ever happened, just as there is a scant basis for conservative claims that Senator Edward Kennedy used a go-between in 1984, in an unsuccessful attempt to involve the Soviet Union in the 1984 presidential election.

Shortly after eight o’clock on the morning of January 20, 1981—inauguration day, Carter phoned Reagan from his desk in the Oval Office. It was likely that the captives would be released within a matter of hours, he explained. It had taken weeks to iron out the details of the agreement, but in the end, the ayatollah’s representatives had consented to cutting the Americans loose in exchange for a transfer of $9 billion in frozen Iranian assets. Carter was dressed in a casual cardigan sweater and open collar shirt. The lines on his face betrayed the many sleepless nights he had passed since the November election. More than anything, he wanted to see the hostages released during his presidency.

At 10:25 a.m., Roselyn Carter called down from the residence to urge her husband to dress for Reagan’s inauguration. In a short while, the Reagans would arrive for coffee and tea, and both couples would board a limousine for the short drive to the Capitol. It was left to Hamilton Jordan, Carter’s chief of staff, to monitor the situation in Tehran and inform Carter the minute that the planes carrying the American hostages took off for Europe.

From his limousine—and then from Air Force One, which was waiting on the tarmac during the inauguration ceremony to shuttle the Carters back home—Jordan kept in close communication with the White House Situation Room. The hostages were sitting on an airport runway in Tehran, awaiting clearance to take off. With one eye on a television in the main cabin on Air Force One Jordan could see the tension in Carter’s eyes. Vice President George Bush had already taken the oath of office. In a matter of minutes, power would be transferred to the new president. After a bruising four years in office and a trying re-election campaign, Carter seemed destined to leave the presidency without realizing his greatest goal.

“I called the situation room on the secure communications system to inquire about the hostages,” Jordan later wrote. “The person who answered the phone asked me to hold on for a minute. He came back on and said he was sorry but the information was not available. ‘But I’m calling on a secure phone,’ I protested. ‘That’s not the problem, Mr. Jordan. Mr. Carter is no longer president, so classified information is no longer available to you.’”

Moments after Reagan raised his right hand to take the oath of office, planes carrying the American hostages began their flight from Tehran.

***

Questions abound regarding the probable Russian hack of the DNC email. Of course, it’s not quite the same: Unlike Richard Nixon, who willfully committed a criminal act by negotiating as a private citizen with a foreign power, Donald Trump almost certainly had no foreknowledge of the attack. In this sense, he was likely just as unwitting a beneficiary of events as Ronald Reagan in 1980. At least, that was the case until this morning, when Trump actively solicited the criminal intercession of a foreign government in a U.S. presidential election. Now, all bets are off.

It seems all but certain that Vladimir Putin has decided to insert himself in the presidential campaign process to punish a candidate whom he doesn’t like (Hillary Clinton) in favor of one with whom he can do business.

Foreign interference in U.S. elections is not, strictly speaking, an entirely unprecedented event. But that fact alone offers cold comfort. Given how close the presidential race is today, Russia’s brazen lawlessness—and Donald Trump’s encouragement of it—pose a decidedly unique threat to American safety and political stability.