mainstream faction; main faction
Refers to the dominant group within a political party, organization, or movement, as opposed to minority or dissident factions.
党内では主流派と反主流派の対立が続いている。
Within the party, conflict between the mainstream faction and the anti-mainstream faction continues.
彼は主流派の意見に従うことにした。
He decided to follow the opinion of the mainstream faction.
主流派 highlights being the numerically or politically dominant group, while 正統派 stresses fidelity to traditional or correct principles.
Compound of 主流 (main current, mainstream) and 派 (faction, group).