The dirty tricks in 1972 were sustained attacks based on faleshoods by the Nixon CREEP against the most popular possible Dem opponent, Sen. Edmund Muskie of Maine, who was finally brought to tears in public, which fatally damaged his campaign, opening the way for George McGovern to get the nomination and take only DC and Massachusetts in the general election. Today Trump and his many allies, both in Congress and on Fox News, have peddled a false story that Joe Biden fired a Ukrainian prosecutor because that prosecutor was investigating Biden's son, Hunter. They said repeatedly during the impeachment trial, and just last night I heard Sean Hannity at it again vociferously, with those on the show all nodding their heads. Today is the New Hampshire primary and results not out yet. But Biden is expecting to do poorly, while Bernie Sanders is likely to win (although might not), with Warren also probably on the fade, leaving Bernie on top on the progressive left end of the Dems. I read some interviews with voters in Iowa who did not vote for Biden because they fear the "baggage" of his son and that the attacks by Trump et al will weaken him like Hillary's emails hurt her in the 2016. But to me, this looks more like 1972 all over again.
Now I like Bernie and have lots of respect for him. I also liked McGovern, and somewhere in July, 1972 I was out in South Dakota and actually thought he might win, although in the end he was unable to take even his home state. I even was an economic adviser of his during his brief run in 1984, when he dropped out after surprising everybody by coming in third in the Iowa caucus (Eleanor had not wanted him to run a all). I provided him with a budget proposal he touted there and got csalled "the conscience of the Democratic Party," but nobody was under any delusions that he had any chance of winning anything, having been ousted from his Senate seat in 1980 in the Reagan sweep (which also took out the Father of Earth Day, Gaylord Nelson of Wisconsin).
Now maybe Bernie would do better than many think, and polls have him not doing all that much worse than some of the other Dem candidates. But in contrast to Warren, he has a lot of Dems against him (although Gabbard and Bloomberg have more), with on that measure Warren the least disliked among Dems of all their candidates. As it is, both Dems and the Trump people have held off going too hard against Bernie, the Dems out of not wanting to anger his loyal followers, and until very recently the Trump people out of wanting to puff him up against Biden the way they puffed him up against Cliinton (and still do. last night Hannity was all over how the Dems screwed him out of the nomination in 2016). But there is a lot that will be dragged out and thrown at him if he gets the nomination that has received little publicity, such as his supporting the Trotskyist Socialist Workers Party canddiates for president in 1980 and 1984 (in 1980 that candidate called for US enlisted men to kill their officers). Unfortunately there is more where that came from, although at least young people do not know who Trotsky was, or if they do it is because he was Frida Kahlo's lover briefly in Mexxico, how cool.
Anyway, I doubt Bernie would get slaughtered as badly as McGovern was in 1972, but it couls be bad enough to throw the House back to being under GOP control as well as keeping Trump in the WH and the GOP in control of the Senate. But then, maybe not. Maybe Bernie will go all the way, or one of the others will surge out and win, although between Buttigieg, Klobuchar, and Bloomberg, they seem to be banging into each other while Bernie has a clear path. In any case, like Muskie in 1972, I think that it will not be Biden, although he is not totally out. A lot of it has been his own weak campaigning and poor fundraising and disorganization, but the dirty tricks by the Trumpsters have certainly played their role as well and continue to do so.