if you can't beat 'em, join 'em
Also, if you can't lick 'em, join 'em. If you can't defeat your opponents you might be better off by switching to their side. For example, Seeing that no one else was willing to stick with the old software program, Marcia learned the new one, noting if you can't beat 'em, join 'em, or I opposed a new school library, but the town voted for it, so I'll support it—if you can't lick 'em, join 'em. This expression dates from about 1940 and originally alluded to political opponents. The opposite idea is expressed in an advertising slogan used in the 1960s and 1970s by a cigarette company, in which the smoker would fight rather than switch brands.