As a complete outsider I would say any Democrat who is capable of defeating Trump. I don't think some Americans realise, or fully appreciate how much damage President Trump has caused to your countries reputation abroad. Far from enhancing it with his caustic brand of diplomacy, he has alienated many long standing allies and sown seeds of doubt and suspicion about America's long term commitment to international peace and stability. Just consider that for a moment and ask yourself if that's a good place to find your country in? The United States surely needs its friends, and your friends need a reliable and honest United States. As things stand, long term friendships and alliances are under great strain; many Europeans find Donald Trump utterly loathsome and totally untrustworthy. I would suggest Joe Biden (with a good running mate) stands the best chance of defeating Trump. He has demonstrated an ability to build alliances and reach across the divide and he has established a solid reputation abroad. These are key qualities that will be necessary in bringing more and more people on board. Rather like the Leader of the Opposition in the UK, Bernie is a polarising figure who has a good and enthusiastic support base, but may struggle with that vital broader appeal that will swing people away from Trump. As for other candidates, forget them. This will be your one opportunity to get rid of Donald Trump and put a stop the chaos and erosion of trust. Voting for anyone other than the Democrat will be a complete stitch up that will hand power back to Trump.