intransitive/transitive to join other people in order to support someone or something when they are having problemsrally behind: Supporters have been quick to rally behind the team.
rally to someone’s defence/assistance/support: Parents rallied to the defence of the school.
rally to the cause (=join other people in order to support something specific): Animal rights groups have rallied to the cause of this endangered species.
rally support (for something) (=encourage people to support something): A demonstration is planned to rally support for the workforce.