You aren't based in the US, are you? I can understand why a British socialist would make this mistake - Bernie does superficially resemble this sort of socialist entryist, and he does superficially resemble succdems like Corbyn, which is why Socialist Alternative critically endorsed Bernie in 2015-2016 and then "critically" endorsed him in 2019-2020. The problem is that this strategy stems from an incorrect analysis of the class character of the Democratic Party, which superficially resembles Blairite Labour but policywise is somewhere between the Lib Dems and the Tories. Labour is supposed to be a social-democratic party, based among the organized working class, but has since been infiltrated and taken over by bourgie libs. Militant's entryism, as short-lived as it was, were much more organized than Sanders or the DSA/Justice Dem entryists could have dreamed of and led Labour to defeat Thatcher before the Blairites seized control and purged them from the party.

The Democrats have always been a 100% bourgeois liberal party, with no internal democratic structure through which working-class membership could push back against the party establishment, or subject their candidates to recall. Since the 1930s the Democrats have functioned as a fail-safe for the ruling class, acting as a fucking black hole sucking away the lion's share of the energy poured into potentially socialist movements. Any initially-socialist politician who's attempted entryism into the Democratic Party, going all the way back to Upton Sinclair, either gets ratfucked and spit out by the party or sells out and turns into a liberal.

If Bernie Sanders was a Trotskyist in the 1970s or even the 1980s, he sure as shit wasn't one by the time he announced his candidacy for the presidency in 2015. Adherence to the principles laid out in Permanent Revolution requires mindfulness of one's loyalty to the international working class, instead of falling prey to the social-imperialist pressures that killed the 2nd International. Since becoming a senator, Sanders has consistently bowed to imperialist pressure from the military-industrial complex in order to protect jobs in his home state of Vermont. He dodged the bullet of voting for the Iraq invasion in 2003 but he signed off on multiple other highly questionable military actions like bombing Kosovo in the 1990s.

Trots don't hide their power level by voting for imperialist policies and hiding the fact that they're (trying to be) revolutionary Marxists, only leaving subtle clues for people looking to validate their perception of them as actual socialists. They don't water down their programs by repeating demands that are already popular with the working class, without fomulating transitional versions of them that point towards the necessity to organize for a revolutionary transition to socialism. They don't get out of the way of the lesser-evil candidate for fear of the spoiler effect when the greater evil is just another reactionary liberal.

Those who call themselves Trots - hell, those who call themselves Marxists or Leninists, for that matter - who flirt with hiding their power level are succumbing to opportunist pressures, like SA started to when they endorsed Sanders and a bunch of DSA entryists. That's the same doomed road that eventually turned the CPUSA into a front for the Democratic Party and an FBI/CIA honeypot after they couldn't take marching orders from the degenerated Kremlin anymore.