Many people say that Rasmussen polls are biased, leaning to the right, politically. Others say that they are representative of the US population, being a serious and professional polling service with a longstanding record. It has been said that they tend to get different results than other major national US polls. Are they right-biased in their sample of the US population, or are other polls biased? Rasmussen did predict Trump's 2016 win, while other polls failed to predict this.

Trump and Mueller
Donald Trump expressed concern that the Mueller investigation was biased against him because there were 13 Democrats (either registered as Democratic, or donated to Democratic Party candidates) and no registered Republicans among its investigators. What are the reasons to believe that the team was biased, and what are the reasons to believe that they were not biased?