under the banner of
idiomPart ofbanner
under the banner of — idiom
1. while supporting, or claiming to support, a particular idea, group, or cause; do
1.idiom
Definition
while supporting, or claiming to support, a particular idea, group, or cause; doing something in the name of a stated set of values.
Example
The volunteers worked all summer under the banner of free public education for every child.
Several small parties joined the election under the banner of a single green movement.