If I had to choose one, it'd be the use of obviously disingenuous and politically motivated accusations of anti-semitism made against the left by liberals that were used to destroy Corbyn and substantially weaken the position of the UK left, as well as, the concomitant creation of a situation in which, in the UK at least, it is close to impossible to publicly express solidarity with Palestinians while retaining a public platform. At least the Russian government actually sucks - even if Russiagate is largely bullshit designed to break liberal boomer's brains and distract them from the fact that the Dems have nothing to offer to anyone who isn't a board member of Goldman Sacs. The anti-semitism stuff is literally a bunch of blatantly racist and islamophobic liberals throwing out apologia for genocide, while calling those trying to build resistance against it fascists.