Christian Lloyd Campbell undoubtedly heard some variation on the law officer’s time-honored pitch: “We don’t want you. We want [insert name of bigger fish]. But we do have you … and you know it. Do you want to eat this whole meal or do the smart thing?”That’s what Karen Manning got, too. And because she and Campbell took the hint from federal prosecutors, they swell in importance from bit players in the John Wiley Price drama to top supporting actors. This is how prosecutors try to work cases, and the feds’ apparent success with these two lower-level Price associates bodes ill for the Dallas County commissioner in his coming political corruption trial.Price, of course, deserves his constitutional presumption of innocence, but the U.S Attorney’s Office has tipped some powerful cards with the guilty pleas by Campbell and Manning in exchange for lighter sentences.