There are many phrases that can be used interchangeably with the phrase "stand behind". Some common synonyms include: support, endorse, back, vouch for, favor, advocate, uphold, champion, defend, and stand by. Each of these phrases conveys a sense of loyalty, commitment, and solidarity with a particular person or idea. Whether you are standing behind a friend, colleague, or political candidate, these synonyms indicate a willingness to offer your full support and defend their interests. By using different alternatives for the phrase "stand behind", you can convey different shades of meaning and nuance to your statements.