After taking the oath of office following Richard Nixon’s 1974 resignation over Watergate, President Gerald Ford famously declared, “My fellow Americans, our long national nightmare is over.”

Ford was mocked for self-serving grandiosity, yet time would prove him correct. The nation was tested by corruption in the Oval Office, but the constitutional system prevailed because good and brave people of both parties confronted the crisis.

Most dramatically, Attorney General Elliot Richardson and his deputy, William Ruckelshaus, resigned rather than follow Nixon’s order to fire special prosecutor Archibald Cox in the Saturday Night Massacre. And Nixon himself resigned when even fellow Republicans signaled they were prepared to impeach and convict him.

One result is that, while “Nixonian” is a synonym for illegal abuse of authority, his resignation and the smooth transfer of power marked a ringing triumph of justice. The fundamental principle that nobody in America is above the law was upheld in practice.

Now imagine another scenario. America wakes up on Nov. 9 to President-elect Hillary Clinton, and to the cold reality that the same principle of equal justice is null and void.

Her election would mean that some people are above the law. It would mean that one of them will assume the commanding heights of our country despite abundant evidence that she committed crimes and got away scot-free.

Oh, for the good old days of Watergate and of public servants like Elliot Richardson and William Ruckelshaus. We should be so lucky now.

Instead, we have a sitting president, Barack Obama, who presided over a corrupt Justice Department and the FBI. And instead of public servants of principle, we have a gaggle of quislings, including Attorney General Loretta Lynch, who put partisanship and their careers ahead of duty.

Rather than ending a national nightmare, a transfer of power from Obama to Clinton would start a new crisis of confidence. Consider the threshold question of whether the Justice Department could ever be trusted to prosecute anyone in public office.

If Clinton is guilty of only “mistakes” and “bad judgment” in setting up a private server, sending and receiving national secrets and destroying thousands of government e-mails, on what fair basis can any public official be held accountable?

Is the bar for prosecution raised or lowered depending on political connections?

Thanks to The Wall Street Journal, we also know the FBI ignored outrageous conflicts of interest among its own leadership while supposedly investigating Clinton and one of her top associates, Virginias Democratic Gov. Terry McAuliffe. The paper reported that the head of the FBI’s Washington office met with McAuliffe as the official’s wife was running as a Democrat for the Virginia legislature, and that McAuliffe funneled nearly $700,000 to her campaign.

That aide, Andrew McCabe, went on to oversee the shoddy Clinton probe, and is now No. 2 in the FBI, second only to Director James Comey. And we’re supposed to believe all this is kosher?

Wait, there’s more. Remember that the FBI failed even to investigate the pay-to-play patterns with donors to the Clinton Foundation while Hillary was secretary of state. Several reported transactions look like straight-up bribery, yet there is no sign a single person in the Justice Department suggested an inquiry.

From start to finish, it is obvious that the FBI gave Clinton special treatment. The failure to empanel a grand jury and issue subpoenas, the granting of five immunity deals to her aides, and the agreement to destroy potential evidence all lead to the conclusion that Comey bent the rules to make sure Clinton was cleared.

Rabid Clinton supporters comfort themselves by insisting that those who do not denounce Donald Trump are unpatriotic or worse. But you don’t have to be a Trump supporter to fear that Clinton’s election would be tantamount to approving her chronic dishonesty in public office, and would open the door to an era of corruption unprecedented in modern times.

If that’s progress, then Richard Nixon got a raw deal.

Ham slam vs. Christie

The ham sandwich did it.

The line that an aggressive prosecutor could get a grand jury to indict a ham sandwich takes on new meaning in the New Jersey Bridgegate trial. More and more, it looks like the goal is to dirty the reputation of Gov. Chris Christie instead of convicting the actual defendants for causing a traffic snarls on the GW Bridge.

Christie’s name comes up in almost every major testimony, yet he was never charged in what prosecutors say was political payback for a mayor who refused to endorse Christie. Moreover, the focus on the Republican governor by prosecutors as well as the defense could undercut the case against his two former aides.

Gov. Cuomo’s name has also come up, and there are reports that both he and Christie, as the officials ultimately responsible for the Port Authority, might be called to testify.

And you thought only Russia had show trials.

Rocky mountain ‘high’ lobbying

Junket alert. A press release says a consultant to Colorado’s largest marijuana dispensary “offers tours to legislators . . . to show them cannabis facilities and products of the highest standard so they can see what the industry can look like in practice.”

So they’re invited just to look

‘Class’ clown Blasio

Sunday’s report in The Post that Mayor de Blasio’s Education Department is counting on failed and tainted educrats to oversee the lowest-performing schools answers forever the question of whether City Hall cares about helping poor students.

No, no, no — a thousand times no. It’s all about the care and feeding of adults who belong to unions.

The report confirms that the plan to fix 94 struggling schools, at a cost of nearly $1 billion extra, is doomed by the same mind-set and incompetence that ruined those schools in the first place. Most should have been closed after years of failure, but de Blasio was determined to reverse just about everything done by his predecessor, Michael Bloomberg.

Bloomy’s policy was to close failing schools after a reasonable period, shake up the staff and reopen them with new leadership. He also supported charter schools.

De Blasio insisted that was cruel, and vowed to spend more money on teachers and services as a sign of compassion to keep the schools open. And he fights charters tooth and nail.

After three years, his ideas have been a bust, costing a colossal amount of money and precious years for the children who are trapped.

On top of the earlier Post report that some of those struggling schools are losing students because parents found better options, the evidence that many of the supervisors are duds ends any hope of progress.

Among them are teachers who faced charges of racial and sexual misconduct, but whose job was spared in disciplinary hearings. Naturally, they are effectively promoted to guide the kids who need the most help.

This is not education. This is a scandal.