biden's proposal, like most of his ideas, strikes me as unworkable and awkward, and perhaps even designed to fail. you don't want your supreme court overturning laws every time a new president gets elected, but that seems like the obvious outcome of his initiative. that's insane, and will turn the country into a legal basket case.
what i'm really getting from this is simply that the democrats are sore losers that want to change the rules of the game because they lost it. they lost control of the court in a fully democratic process and they'll have to accept the will of the people, until they can win it back.
mandatory retirement, however, would be a good way to put a maximum age limit on the justices, to ensure they're not completely out of touch with reality, and aren't senile in office, like the president. perhaps that is the best way to look at this proposal: it is as incoherent as biden is generally these days, and evidence that he ought to remove himself from office.