MORE: Well … I believe, when statesmen forsake their own private conscience for the sake of their own public duties … they lead their country by a short route to chaos.

Robert Bolt (1924-1995) English dramatist

A Man for All Seasons, play, Act 1 (1960)
    (Source)

Speaking to Wolsey about why he opposes Henry taking a new wife, even if the alternative is another civil war.

Bolt's 1966 film adaptation uses the same line.