Prosecution of political rivals politicizes the Justice Department, and in the most damaging way. Sure, the attorney general works for the president. But in a free society, prosecutorial judgments should be, and should be perceived to be, objective – rooted only in the law and the facts. Whenever national prosecutors pursue a political opponent of their president, many people will ask, naturally enough: What is the real motivation here?

Such prosecutions have the additional vice of intensifying a nation’s political divisions. They suggest that one side has been led by criminals, possibly even traitors. They announce to the millions of people who supported the president’s political opponent: You favored a crook.

For purely partisan reasons, some people will cheer any such prosecution, and others will rage and mourn. After an election, it is far better to accept Abraham Lincoln’s suggestion, offered in a time of Civil War, that we should “bind up the nation’s wounds.”