under the banner of
under the banner (of) (something)
1. Identifying oneself with a particular title, slogan, etc. Before they officially formed their nonprofit as you know it today, they went under the banner "Green Jobs for Good."
2. With the stated support for or of something. This usage is always followed by "of (something)." We're holding the rally under the banner of equality and tolerance. All are welcome.
See also: banner