When it’s warranted, a motion to disqualify the opposing counsel can be a potent weapon. But lawyers should use that weapon rarely and should resist the temptation, or a client’s importuning, to use it merely as harassment.

The temptation to file a motion to disqualify is often strongest in contentious civil litigation in which bitterness between the parties runs high. In such “grudge matches,” for example, litigation between former business partners — each of whom feels betrayed by the other — or in lawsuits alleging fraudulent conduct, a motion to disqualify offers an attorney the allure of striking a pose as the enforcer of virtue, placing the ethics and integrity of the other side up to scrutiny.