Donald Trump's 2016 presidential campaign will be long remembered, but not for any reasons that will make the Republican standard-bearer or his party proud.

He reached a low point this week when he refused to commit to accepting the outcome of the November 8 election, sending shock waves throughout the political landscape. It was an unprecedented announcement and elicited an audible gasp from the audience at the third and final presidential debate Wednesday evening in Las Vegas.

"This was radical, a deliberate threat," said presidential historian Michael Beschloss.  "It's horrifying" and will be remembered 50 years from now.

Instead of recanting, he doubled down, fanning the flames of the firestorm he ignited. He would accept the verdict of the voters but only "if I win."  And if he didn't like the results, the hyper-litigious businessman threatened to tie up the presidential succession in the courts.

It is a vow to be taken seriously coming from a thin-skinned narcissist who has shown himself totally incapable of admitting mistakes or taking responsibility much accepting less defeat. It something goes wrong, it has to be someone else's fault. He's already begun spreading the blame to the media and to leaders of his own party plus everyone in between.

Many Republican leaders moved quickly to denounce his pronouncement. They essentially agreed with Hillary Clinton, who called Trump's pronouncement "horrifying." 

Trump contradicted what his daughter Ivanka,his running mate, Indiana Gov. Mike Pence,  and other campaign surrogates had said shortly before the debate, namely that there was no question that the Republican candidate would respect the results of the election.  After the debate Pence tried to do another of his 180 turns in order to sound loyal to the boss, but no one was buying. Not only were he and the surrogates unconvincing but they were soon contradicted by the boss.

When moderator Chris Wallace of Fox News asked Trump if he would "absolutely" accept the voters' decision, the candidate said "I will tell you at it at the time.  I will keep you in suspense."

"He was disrespecting the democracy of the United States," said one member of an MSNBC focus group.

Twice in response to an incredulous Wallace's questions, Trump refused to say he would respect the decision of the American people.  This is likely to put further strain on Trump's deeply troubled relationship with Republican leaders, who fear this could create negative ripples on down ballot elections that could cost the GOP control of one or both houses of Congress.

He is laying the groundwork to delegitimize Hillary Clinton if she is elected the first woman president just as he spent years trying to delegitimize Barack Obama as the first African-American president.

It won't end November 9.  Donald Trump is a man who holds grudges deep and long. A dozen years after being passed over for an Emmy for "The Apprentice," he is still bitter, accusing the Television Academy awards of being rigged, one of his favorite words.

For someone six-foot-three and 236 pounds, Donald Trump really is a very small man.