Isn’t this the one thing you know from Edmund Burke, an Irishman and political thinker? You didn’t even know he was Irish. All you knew about Burke was that he said the above quotation. Except he didn’t.
What he said that closely resembles this comes from his 1770 book, Thoughts on the Cause of the Present Discontents.
No man, who is not inflamed by vain-glory into enthusiasm, can flatter himself that his single, unsupported, desultory, unsystematic endeavours are of power to defeat the subtle designs and united Cabals of ambitious citizens. When bad men combine, the good must associate; else they will fall, one by one, an unpitied sacrifice in a contemptible struggle.
Now this is curious. Burke is arguing in favor of unity, of banding together to oppose “ambitious citizens” who have already united their efforts. We could call them The Establishment or a number of other things. Burke’s point appears to be that virtuous people should not believe their individual virtues, their personal choices, to be effective against those who are working together to oppose us.