While you should vote for the best possible option, I feel like these kinds of posts are constantly shifting responsibility away from Democrats for their own short-comings.

A couple of weeks ago I voted in the European Parliament elections for the option that had, in my view, the best possible agenda: socially progressive, ecologist, economically left-leaning, decent foreign policy and coherent voting records. But the campaign they ran was absolutely terrible, starting by the candidate. Even though she is admittedly an accomplished woman who has had a very solid career, she doesn't know about the concept of charisma. She wasn't selected because she was the person who would perform the best in debates or in speeches (and she definitely wasn't), but rather, because she was an option that would provoke little conflict among the different factions of the coalition. That was the sign that the internal dynamics of the coalition had degenerated and were acting out of their own inertia, rather than seeking the best possible outcome.

Expectedly, we got about half the seats we were aiming for.

The very next day, the leader of the coalition resigned from that position. Even though she's a great minister (making policy), she's proven she isn't good at keeping the aparatus under control in order to achieve good results (doing politics). It's a painful process, but a necessary one where mistakes and short-comings must be admitted in order to grow into something more virtuous.

Having read US liberals for years, I grow more and more convinced that they're instinctively hostile to constructive criticism of their party's aparatus. And, when your country's voters declare themselves to agree far more with your party's policies than those of their direct opponent, and yet they can't bury their opponent into irrelevance, you have to admit that your party is doing electoralism wrong, and must question why.