break ranks

1. Fall out of line or into disorder; also, fail to conform, deviate. For example, The recruits were warned that they must not break ranks, or Harry was told to adhere to the party platform and not break ranks. This idiom uses rank in the sense of “soldiers drawn up in line,” and the term originally referred to their falling into disarray. The figurative usage dates from the mid-1800s.

Example Sentences

They’re “mavericks,” “outsiders,” principled conservatives who are willing to break ranks to stand up for what’s right.

From Slate

Congressional Republicans could find it harder to keep their members behind Trump's bill with Musk providing rhetorical – and, perhaps financial – air for those who break ranks.

From BBC

Greene is not the only Trump ally to break ranks with the president's controversial bill.

From Salon

Yoon’s party holds 108 seats, meaning impeachment will require eight or more of them to break ranks.

From Los Angeles Times

A vote study by CQ Roll Call found her the second-most likely House Democrat to break ranks.

From Los Angeles Times