One of Trump’s Oldest Tactics in Business and Politics: I’m Rubber. You’re Glue.

Days before the Iowa caucuses, former President Donald J. Trump is appearing twice in court this week — on Tuesday in Washington and Thursday in New York.

He was not required to attend either hearing. But advisers say he believes the court appearances dramatize what is fast becoming a central theme of his campaign: that President Biden — who is describing the likely Republican nominee as a peril to the country — is the true threat to American democracy.

Mr. Trump’s claim is the most outlandish and baseless version of a tactic he has used throughout his life in business and politics. Whenever he is accused of something — no matter what that something is — he responds by accusing his opponent of that exact thing. The idea is less to argue that Mr. Trump is clean than to suggest that everyone else is dirty.

It is an impulse more than a strategy. But in Mr. Trump’s campaigns, that impulse has sometimes aligned with his political interests. By this way of thinking, the more cynical voters become, the more likely they are to throw their hands in the air, declare, “They’re all the same” and start comparing the two candidates on issues the campaign sees as favorable to Mr. Trump, like the economy and immigration.