Some evidence suggests that moderate candidates fare better electorally than more ideologically extreme candidates, said Brewer. "I think Elizabeth Warren has benefited somewhat in that Bernie Sanders has been in the race and Democrat primary voters perceive her as being between Sanders and Biden. They might perceive her as being more moderate than they would without Sanders there as a contrast."
Despite the united front by Democrats on impeachment and the defense of former Vice President Joe Biden on Ukraine accusations, Biden's campaign may struggle even after an impeachment trial, Brewer said. "Given the source, a lot of Democrats might not believe these allegations about Biden. But in a general election, even unfounded allegations can be potentially damaging. I think the Biden campaign has a lot to figure out going forward on how to deal with this."
The Iowa caucuses will be held on February 3, and the New Hampshire primary is set for February 11.