President Harry S. Truman speaks from Washington on April 25, 1945. (AP)
Stephen F. Knott is a professor of national security affairs at the United States Naval War College.

In the past week, in an effort to prevent a blue wave on Election Day, President Trump has traveled the country attacking Democratic candidates as a threat to American democracy. He may travel by plane rather than train, but the president is drawing on the playbook of the man who became known for the “whistle-stop” campaign more than 70 years ago: Democrat Harry S. Truman.

By taking his message directly to the American people by train, Truman came from behind to defeat New York Gov. Thomas Dewey (R) in 1948 in one of the greatest upsets in American history.

While few would compare Truman’s presidency to Trump’s, they share a crucial characteristic tactically: Like Trump, Truman pulled the upset by fearmongering and appealing to Americans' worst, not their best, impulses.

Truman deserves much praise for his handling of several crises, including the Berlin blockade, the Korean War, the founding of America’s Cold War doctrine and infrastructure, as well as his courageous pursuit of civil rights for African Americans. But as much as Truman’s commitment to civil rights was the stuff of magnanimity and statesmanship, his 1948 campaign for president was the epitome of demagoguery.

Despite his vile tactics, Truman’s whistle-stop campaign has since become something of a mythical event in American political history. Admired by both Democratic and Republican political operatives, this playbook has ingrained character attacks in electoral politics. The tale of a sprightly haberdasher barnstorming through remote villages across the nation, overcoming remarkable odds and defeating a member of the East Coast elite, has reverential status and enormous staying power.

Truman’s whistle-stop campaign involved 352 speeches spread out over three trips, in a 17-car train that covered 31,000 miles in 33 days. Public opinion polls indicated he would be easily defeated, an assessment shared by the press and political insiders from both parties. The Roper organization stopped polling two months before the election, convinced Dewey’s lead was insurmountable.

Against the counsel of some advisers, Truman escalated his rhetoric as Election Day approached, in a desperate effort to carve a path for reelection by tarring his opponents as un-American.

Before 1948, presidential elections had occasionally degenerated into attacks on the character and patriotism of the opposition. The elections of 1800 and 1828, to name two, devolved into this, but those attacks were generally carried out by newspaper surrogates, with presidential candidates maintaining a discreet distance. Truman changed that. In fact, the election became a referendum on personal attacks from the candidate himself.

Dewey — a moderate, which made Truman’s slanderous charges of extremism all the more absurd — presented himself as a man of principle who renounced factional appeals and promised to govern in the national interest. In a way, Dewey’s campaign harked back to a notion of presidential selection from the early republic, presenting him as a figure of national unity and avoiding strident partisanship.

But this was no match for a candidate prepared to use “brass knuckles,” as one of Dewey’s supporters noted while adding, “it is poor judgment to defend oneself with a powder-puff.” The supporter presciently added that Truman was “creating hatred between citizen and citizen and class against class.”

Truman’s train carried a cargo of half-truths and misrepresentations. On some occasions, the president made as many as 16 stops per day, traveling long into the night defending his “Fair Deal” policies and urging voters to support him in November.

The Republican Party, the president warned voters, were fascists on par with Adolf Hitler and Benito Mussolini. On Oct. 26, 1948, Truman claimed the parallels were obvious: “When a few men get control of the economy of this nation, they find a frontman to run the country for them. Before Hitler came to power, control over the German economy passed into the hands of a small group of rich manufacturers. . . . So they put money and influence behind Adolf Hitler.” With Dewey serving as the Hitlerian puppet for nefarious interests, he would take the nation down the same path as Germany in the 1930s. “That’s what the Republican candidate calls ‘delivering for the future,’" Truman added. “Is that the kind of future you want?”

Truman’s crude populism worked, as he barnstormed the country accusing his opponents of being “gluttons of privilege” and “cold men . . . cunning men. And it is their constant aim to put the government of the United States under control of men like themselves.” These men would pave the way for “big business” so they could “take the country over, lock, stock and barrel.”

Not only did Truman accuse his opponents of being fascists, he also accused Dewey of working in concert with communists. “The Republicans,” he claimed, “have joined up with this communist-inspired third party to beat the Democrats.”

Dewey refused to punch back, and that, coupled with Truman’s ability to dominate the news cycle with his incendiary rhetoric, contributed to Truman’s surprise victory. His win ensured “going negative” would become the dominant mode of modern presidential campaigns. As one chronicler of the campaign of 1948 has put it, to achieve victory, Truman was “willing to sow dissension, stir up fear, and slander his opponents.”

On the campaign trail, Truman was a remarkably small and petty demagogue who seemed unable to distinguish between his political fortunes, those of his party and the office he held and all that it represented. In his first attempt to win a national election without Franklin D. Roosevelt, he decided to win at any cost.

One admirer of Truman’s whistle-stop campaign was Roger Stone, a former adviser to Trump’s presidential campaign, who rightly noted the similarities between the frenetic pace and no-prisoners tactics of Truman and Trump in the closing days of their respective campaigns. Trump, as Stone observed, “was copying the playbook of peppery and determined Harry Truman” and both campaigns were “a campaign of us and them, of anger and bitterness, of the haves and the have-nots.”

While Trump’s demagoguery has been widely, and rightly, condemned, Truman frequently found himself in the top 10 of those scholarly polls of presidential greatness. Truman was admired for his decisiveness in confronting an array of crises, for being a president who tried to tackle the pressing moral and international problems of the day. But perhaps the biggest crisis we now confront as a nation — the scorched-earth approach to electoral politics — is one of his own making.