The phrase "get behind" is commonly used to describe support for a person or cause. There are several synonyms that can be used to express this sentiment. "Support" is an obvious choice, but other options include "back," "champion," "endorse," "advocate for," "promote," "stand by," and "root for." These alternatives can add variety and depth to writing, helping to avoid repetition of a single phrase. When selecting a synonym, consider the tone and context of the message being conveyed, and choose a word that best reflects the intended meaning.