Forty years ago Sunday — at 2:30 a.m., June 17, 1972 — security guards apprehended five burglars attempting to break into and wiretap Democratic Party headquarters on the sixth floor of the Watergate Hotel in Washington, D.C.

An FBI investigation into the crime revealed a sordid conspiracy that two years later prompted President Richard M. Nixon to resign in disgrace.

“During their Watergate investigation, federal agents established that hundreds of thousands of dollars in Nixon campaign contributions had been set aside to pay for an extensive undercover campaign aimed at discrediting individual Democratic presidential candidates and disrupting their campaigns,” Washington Post reporters Bob Woodward and Carl Bernstein reported in a story published Oct. 10, 1972.

Clandestine activities condoned by the Nixon White House included “following members of Democratic candidates’ families and assembling dossiers on their personal lives; forging letters and distributing them under the candidates’ letterheads; leaking false and manufactured items to the press; throwing campaign schedules into disarray; seizing confidential campaign files; and investigating the lives of dozens of Democratic campaign workers,” Woodward and Bernstein wrote in their groundbreaking exposé.

Nixon’s henchmen targeted Maine Sen. Edmund Muskie because the president and his aides perceived Muskie to be their greatest threat to re-election in 1972. According to Woodward and Bernstein, Nixon’s campaign paid Muskie’s chauffeur $1,000 a month to pilfer internal memos, position papers, schedules and strategy documents.

In a Washington Post retrospective to mark the 40-year anniversary of the Watergate break-in, Woodward and Bernstein assert that, in a five-pronged attack on anti-war activists, the media, Democrats, justice and history, Nixon contemplated such schemes as enlisting priests to deliver hush money, recruiting mugging squads to bash anti-war protesters and stationing prostitutes wired for sound on a yacht near the Democratic convention in Miami Beach.

Campaign shenanigans are an American tradition. They cross party lines and certainly weren’t new in 1972.

But the depth of the Nixon administration’s orchestrated, systematic treachery — and the scar it left on the American body politic — can and should not be erased by a presidential pardon or partisan apologists seeking to portray Watergate as poorly executed political business as usual.

Driven by paranoia and power lust, Nixon gutted the optimism that placed post-World War II American society at the forefront of social and technological revolutions — for the betterment of humankind — and replaced this nation’s signature idealism with a poisonous “mass adversarial cynicism,” in the words of New York Times columnist David Brooks, that continues to define our approach to politics — and life.

The roots of today’s vicious, republic busting “us versus them” application of governance at the administrative, legislative and judicial levels rises like Satanic spawn from the Nixonian mind-set that manifested itself in acts such as the Watergate break-in and sabotaging of Ed Muskie and other men of integrity.

Watergate remains a defining moment in American history — one that obliterated public trust in elected officials and drove a permanent wedge between the populace and those entrusted to govern us.

We will never be the same.