Last January, before the first primaries and caucuses, I predicted in a luncheon talk before the Idaho Falls Rotary Club, that Hillary Clinton and Donald Trump would become the candidates of their respective parties in the 2016 presidential campaign. Jaws dropped when I explained why Trump would defeat a field of 15 GOP candidates, most of whom enjoyed considerable experience in American politics and governance.

I wish I had been wrong. I told the audience that, at that juncture, Trump was a Republican problem. When officially nominated, I noted, he would become an American problem. That is true; Trump is an American problem.

The United States’ presidential electoral history has never seen the package of problems posed by Donald Trump. He is a practiced master of the art of innuendo, traffics in conspiracy theories, mocks reporters with disabilities, utters racist and misogynistic remarks, and advances as “facts” stories that fact-checkers repudiate. All of that is familiar and documented. All of that is repugnant, alarming and beneath the dignity of a presidential nominee, as Mitt Romney has rightly noted.

Trump stands apart from previous presidential nominees in his repeated allusions to the availability of violence to curb the candidacy and influence of Hillary Clinton. At a rally last week, Trump stated that Secretary Clinton’s bodyguards should “be disarmed.” Then, he declared, we would “find out what happens to her.” He concluded, “that could be very dangerous.”

These remarks follow on the heels of his warning in August that if Clinton were to win the presidency and proceeded to nominate judges who fit her views, Second Amendment rights of Americans would be “gone.” At that point, he said, “it would be too late,” although “maybe the Second Amendment people could do something about it.”

Apart from the sheer demagoguery of his remarks — Clinton has never threatened to take away Second Amendment rights — it is distressing beyond measure that a candidate for the presidency would resort to allusions of violence against an opponent. Trump is playing with fire. The tragic history of assassination in this nation, not to mention the parameters of basic human decency and the principles of democracy, forbid such distressing talk.

For centuries, it has been understood that certain circumstances must obtain in a nation if it wishes to be regarded as a democracy. Of those conditions, one has been paramount: Rejection of violence, coercion and intimidation, as means of pursuing a political agenda or an electoral outcome. Democracy is a system premised on vigorous discussion and debate — tools which require respect and protection, lest they cease to be means for contemplating, analyzing, supporting and voting on policies and laws that would govern the nation.

The absence of violence as means of making changes in the American Republic was critical to the Framers’ enterprise. They hoped, as Alexander Hamilton wrote in Federalist No. 1, to create a constitutional system in which citizens might govern through deliberation, rather than suffering the forceful imposition of government upon them. The Framers hoped that they had instituted a system in which peaceful change, including the peaceful transition of power, would replace what the world had seen across the years: Change of power through violent means.

Like violence, the tools of coercion and intimidation, whether grounded in religion, racism, sexism or economics, to alter politics or affect the outcome of elections, are repugnant to the principles of democracy. It is why, for example, the presence of the KKK or similar white supremacist groups represent a profound danger to the health and vitality of the republic.

Violence, including assassination, denies citizens the right to make fundamental choices about candidates, policies and laws. Certainly it denies the premise of popular sovereignty and the right to create a government grounded in the views and values of the citizenry. Violence, moreover, may overturn the will of the people. Without doubt, it short-circuits political participation, as the world has come to know in its observation of political violence across the globe.

Hardly anybody expects a presidential election to be free of exaggerated rhetorical attacks, misrepresentations of opponent’s records and positions, and false promises. Those things occur, regrettably, which is why, for the sake of voter education, independent fact-checkers have assumed great importance in electoral campaigns and governance practices. They become vital means of governmental accountability.

But candidates should forswear, absolutely, any encouragement of violence. There is nothing funny about it, certainly, and votes won on the basis of it can be but hollow victories, unworthy of those cast in favor of Washington and Lincoln, Roosevelt and Reagan. Promotion of violence, in any form, is anathema to America’s political traditions. Supporters of candidates who encourage it or flirt with its possibilities should carefully evaluate the temperament and character of the person behind those words.

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Dr. David Adler is President of the Alturas Institute, created to advance civic education and the Constitution. He is co-author of the forthcoming book, “The War Power in the Age of Terrorism: Debating Presidential Powers” (Palgrave MacMillan).