When you give a bully your lunch money, you only teach him to come back for more.

I learned that lesson when I served as US Attorney in Detroit, where we prosecuted a number of public officials for extortion. When businesses found themselves shaken down for kickbacks in exchange for receiving government contracts, those who acquiesced may have found momentary relief by paying a bribe, but the extortionist always came back for more.

I have been thinking about these extortion cases as President Donald Trump continues to target law firms with executive orders. Five major law firms have now been named in presidential orders that strip lawyers of security clearances, cancel government contracts, prohibit federal agencies from hiring former employees, and ban them from entering federal buildings, a major problem for lawyers with cases in federal court. The firms appear to have been targeted because they employ, or have employed in the past, lawyers who have worked on cases against Trump, such as special counsel Robert Mueller and former Justice Department lawyer Andrew Weissmann. One firm, Covington & Burling, appears to have ended up in the crosshairs because it provided pro bono legal services to special counsel Jack Smith.

Some firms have chosen to fight back by challenging the constitutionality of the orders in court. All three law firms that have sought temporary restraining orders—Perkins Coie, Jenner & Block, WilmerHale—have succeeded. Courts have found that they have shown a substantial likelihood of success on the merits of their claims that the orders violate the First Amendment right to free association, among other constitutional protections.

But two law firms have taken a different route. Paul, Weiss and Skadden, Arps, Slate, Meagher & Flom have instead cut deals with the Trump Administration, each agreeing to provide tens of millions of dollars in pro bono legal services to causes approved by Trump. Both are prominent, New York-based, global law firms with previously stellar reputations. Paul, Weiss was reacting to a presidential order targeting it by name. Skadden didn’t even wait for an order, entering into a deal to preempt one. Their desire to make the controversy go away is understandable, but their appeasement is not only disappointing to other members of the legal profession, it is also unlikely to succeed.

As I learned from those extortion cases, corruption breeds corruption. The first payment of a kickback is rarely the last. The corrupt politician learns who will cave in to pressure, and he exerts more. Once a victim pays a bribe or kickback, there is nothing to stop the powerful official from demanding more payments simply to preserve the status quo. In addition, he also learns that if he was able to find one victim, he can likely find others, so he will continue to use corrupt tactics in hopes of more paydays.

No doubt, the target of an extortionist is in an unenviable position. I saw small construction firms land lucrative government contracts to install a sewer system or repair a water main only to face the painful decision of paying a kickback or losing the work. When confronted with a demand to pay, the owner faces loss of revenue, deprivation of future business opportunities, damage to their reputation, and sometimes even fear of physical harm, threats, and harassment. They worry not just about themselves, but about their other clients, their employees, and even their own families, all of whom will be affected if they incur the wrath of a powerful political leader. As a result, it can be very tempting to give in to the demands for payment in hopes that the threat will disappear. But it never does. Some of those business owners found themselves paying again and again. Some were even charged as defendants in bribery conspiracies.

Similarly, when law firms pay off Trump so that they can simply do their jobs, they invite more demands on themselves, and they empower him to find other law firms to bend to his will.

Of course, the real blame lies not with the victims but with the extortionist. Here, we have a president who is making good on his promises of retribution. While he seems happy to take the pro bono services, what he likely really wants is submission. He wants to teach lawyers a lesson that if they go after him, they will pay a heavy price. He wants to deter lawyers from taking action against him in court and for law firms to shun any lawyers who do.

But as every school child learns, the only way to prevent the bully from coming back for more is to refuse to give in to his demands.