In times of great tumult and change, we often think we are going through something unique. This is simply not true about what we are seeing with Donald Trump and this presidential election, writes Bruce Wolpe.

Washington. The Republicans have been here before. Big time. More on that in a moment.

For this week in Cleveland, the potency and limitations of Trump have been on vivid display. Trump's forceful speech was a necessary bookend to a week of events that showed an organisation that simply under-performs and makes stupid rookie errors in the big league of presidential politics. The absence of the party's leaders and past presidents from the hall spoke volumes of a party badly divided, underscored by the unrepentant siren song of Ted Cruz.

What we do not know is if Trump's clarion to make America great again, to make America safe again, to make America first again, to upend America's presence in the world by tearing up security and trade agreements that reach every corner of the Earth, to push every bad button on immigration, religion, and race with his message of abject fear and relentless turmoil, all in order to divide - and conquer - America:

We do not know - yet - whether Trump has moved the nation - through these policies and the vicious attacks on Hillary Clinton's character and experience - or just reinforced the base that he has. Indeed, the delegates in the hall do not look like America, or reflect today's America.

Ronald Reagan, the great Republican hero, projected his conservatism with optimism, and he won the country. Trump projects belligerence and anger; he yells at us, and believes we will follow.

In times of great tumult and change, there is often a facile arrogance that we are going through something unique - that what we are witnessing has not happened before. This is simply not true about what we are seeing with Trump and this presidential election. And there are lessons from that history to guide the outcome this November.

The last time in the modern American political era (post-1960, with JFK) that the Republicans met and nominated a radical for President was in 1964, when Senator Barry Goldwater, Republican of Arizona, as fervent an ideological conservative as America has known, engineered a takeover of the Republican Party - a populist uprising that overthrew the establishment.

Battle of the buttons: Barrie Goldwater's presidential campaign in 1964 divided voters sharply.

Those events were best chronicled by the legendary Theodore H White in his magnificent The Making of the President: 1964 - the successor to his breakthrough history of the same title of the 1960 election. White's was the template for all subsequent campaign reporting in the age of television, computers, mass media advertising, and polling.

Goldwater bubbled up, rocked, seized and split the Republican Party. To his avid supporters, he was an incendiary leader of uncompromising vitriol; they flexed their muscles and voices in state after state to utterly conquer the old guard.

There was Goldwater the man with the reckless and wanton words. White recounts:

Goldwater's candour is the completely unrestrained candour of old men with little children… He had suggested the use of atomic weaponry by NATO commanders … he had advocated withdrawal of recognition from the Soviet Union, and the abolition of the graduated income tax.

Loose nukes! And not a wall - but in the same spirit: "Let's lob one into the men's room of the Kremlin," Goldwater said. "Sometimes I think the country would be better off if we could just saw off the Eastern Seaboard and let it float out to sea."

There was also a massive stop-Goldwater movement in the run-up to the Republican convention, led by a Romney (Mitt's father) and other Republican governors, who implored their party with this appeal:

In short, Goldwaterism has come to stand for a whole crazy-quilt collection of absurd and dangerous positions that would be soundly repudiated by the American people in November.

They were right - but they utterly failed to stop him. Goldwater was, White wrote, "if not the captain, at least the emblem, of a major coup d'etat in American politics." The party was at war with itself internally: "The Republican Party had split in two" over Goldwater, White wrote.

Goldwater's image was highly defined by the time he won the nomination.

This was the fundamental Goldwater problem - himself… How could he break the image that was fastened on him? How could Goldwater erase the cartoon of himself? How could he break through the web of opinion-makers?

He could not of course. Goldwater led to the most disastrous Republican rout in the 20th century.

President Lyndon Johnson and the Democrats hammered the nominee mercilessly for his zealotry, radicalism, recklessness, and unfitness for office. Dangerous world events instilled fear. We have Orlando, Brexit, Dallas and Nice. Well, one month before the 1964 election, Khrushchev was ousted from power in Russia, Red China exploded its first atomic bomb, and the Tory government in the UK was defeated at the polls. The world looked like hell, was under threat and unstable.

The President explained these wrenching events to the American people - and they trusted him to navigate those crises with steady, experienced leadership.

This was Johnson a few days before the election:

Just because we are powerful, we can't just mash a button and tell an independent country to go to hell because they don't want to go to hell and we don't get very far rattling our rockets or lobbing them into the men's rooms or bluffing with our bombs.

There was no way America would really turn to an untested man who could be capable of doing anything.

In the wake of that November's landslide defeat for Republicans, White captured what it meant for their party:

Strategy must begin with a vision - a perception of the nature of America as it has changed, with all its promises as well as its menaces; and the greatest split in the Republican Party is not geographical, or even governmental, but between those whose dreams lead forward and those whose dreams lead back.

They face exactly the same issue today. This was the message of Jeb Bush, whom Trump thrashed and trashed, to his party on the eve of this extraordinary convention.

The past is prelude here; 2016 should not be that different from 1964.

Bruce Wolpe was on the Democratic staff in Congress in President Obama's first term. He is a supporter of Hillary Clinton's campaign.He is chief of staff to former Prime Minister Julia Gillard. The views posted here are solely and exclusively his own.