I hate to break it to you, but for the most part, neither the Republican party or the Democratic party in the US act in the interests of the people. The difference between them is quite simple, one is openly socially conservative and the other is less so. Fiscally, they are both conservative and forceful in keeping the American status quo.
Biden has come out of the blue to go head to head with Sanders. Despite appearing past it to some, Biden is the preferred choice amongst the Democrat establishment. With his lack of ambition and unwillingness to face up to high degrees of the class inequality in the US, he makes a perfect fit. He is the man who would keep America the same as it's been for the last 50 or so years, but does makes the country appear more liberal. In the grand scheme of things, a vote for Biden means nothing; even if he could win, nothing will change.
Media outside the arena of social conservatism like to paint a picture of how Trump has dramatically worsened America but he hasn't. It is literally the same. While people may be more confident in making slurs against ethnic minorities now, that attitude was always there. The only way to change these views is through a complete societal upheaval, something not on offer by either of the big parties. It takes the destruction of the establishments to bring such change.
I hear the cries, "oh but Bernie is different". Indeed, he is. However, when part of such an establishment, it still counts for nothing. He may be able to make a couple of reforms to make healthcare better or combat climate change but it will not be enough to combat the struggle working Americans face. Actually, he will most likely disrupt the path towards class consciousness currently developing in the US. Bernie Sanders is selling the idea that he is the answer to giving workers power but what actually is on offer is a slight improvement in healthcare and not much else. This will lead to disappointment amongst workers and ultimately, they will leave the movement.
So, is 'Medicare for all' alone worth the vote if Sanders wins nomination? No. This policy simply nationalises insurance; there's still room for pharmaceutical companies to charge extraordinary prices, and there's no guarantee on absolute free healthcare. As for the issue of climate change, without a planned economy, we cannot stop its trajectory. Under the current neo-liberal regime, which Sanders would not end, we still have a constant cycle of over-production, pollution and deforestation.
It is clear that there is no answer to a better America in the short term. But if you are American, don't waste your vote. Vote for the third parties that speak to you, whether it is the Greens, Libertarians or whoever else, take the votes away from the establishment parties. Show that you will not be subjected to this unfair two party system. I don't care for parliamentarism but I realise it can make a difference, something no Democrat or Republican can ever commit to. Of course, a third party will not win this election, but by voting for them, it can widen the debate and in the long term, there may be real change on the table.