From the LA Times back in October
Nixon tried to tamper with the 1972 election when he was seeking a second term. First he sent undercover agents to sabotage the campaign of Sen. Edmund S. Muskie of Maine, the Democrats early front-runner.
Then Nixons ham-fisted plumbers broke into a Democratic Party office in Washingtons Watergate complex to plant listening devices, only to be thwarted by a security guard. A two-year-long whodunit revealed numerous other crimes. Nixon quit after Senate Republicans warned him hed be ousted from office in an impeachment trial.
https://www.latimes.com/politics/story/2019-10-13/trump-scandal-beginning-to-smell-a-lot-like-watergate
and the Roger Stone connection was looked at in Slate, but focusing on Nixon's use of Vietnam in 1968 to influence the election-but still treasonous nonetheless.
Nixon, then a former vice president, had the same goal as Trump: To undermine a leading opponent, in that instance Vice President Hubert Humphrey, who was the Democratic nominee in the chaotic election of 1968. In a nation already traumatized by the assassinations of Robert F. Kennedy and the Rev. Martin Luther King Jr., Humphrey was a compromise candidate tarnished by his association with Lyndon Johnsons deeply unpopular war in Southeast Asia. Nixon correctly perceived that as a weakness and exploited it.
Trump appears to have pursued similar dirty tricks against former Vice President Joe Biden, whom polls have suggested would defeat Trump easily as a potential Democratic nominee next year. In fairness, why wouldnt Trump pursue such tactics? They worked against Hillary Clinton in 2016, who was perceived by many voters as untrustworthy and plagued by scandal, based largely on false rumors, leaked documents and innuendo. At least until now, Trump has suffered no serious consequences for his 2016 campaign, just as Nixon didn't in 1968.
https://www.salon.com/2019/09/28/nixons-the-one-trumps-misuse-of-foreign-policy-echoes-tricky-dicks-vietnam-meddling-in-1968/