The phrase "is in favor of" can be replaced by a multitude of terms, each with its own unique shade of meaning. Some synonyms include "supports," "advocates," "promotes," "endorses," "backs," "champions," "favors," and "approves of." Each of these words signifies a degree of agreement or alignment with a certain position or argument. "Supports" and "advocates" generally connote a more active form of encouragement, while "endorses" and "approves of" suggest a more passive or formal stance. Ultimately, the choice of synonym depends on the specific context and message that the writer intends to convey.