THE U.S. Secret Service has a tough job — protecting the president and other top federal officials — which, by and large, it performs capably and professionally. Indeed, for many years its reputation for bravery and effectiveness has been right up there with the Navy SEALs and other elite American fighting forces.

Lately, though, you are more likely to hear late-night comics making jokes at the Secret Service’s expense. The reason is obvious: embarrassing episodes of frat-boy behavior, both overseas and in the United States, culminating in this week’s report of an agent getting drunk and passing out in a Netherlands hotel corridor. These have cast the agency, fairly or not, in a deeply unflattering light. Given the importance of the Secret Service’s task, this is no laughing matter.

In a way, the latest incident is the most troubling precisely because it happened after the Secret Service was supposed to have cleaned up its act. In 2012, several agents were fired or disciplined for getting drunk and hiring prostitutes while in Cartagena, Colombia , doing advance work for a pending visit by President Obama. Among the new policies instituted after that disaster was a directive barring the consumption of alcohol within 10 hours of going on duty. That rule appears to have been violated by the passed-out agent and two others in the Netherlands — notwithstanding that they had been fully briefed on the policy and specifically warned by their supervisor before going out on the town.

Several men who behaved inappropriately in Colombia and the Netherlands were members of a paramilitary unit within the Secret Service known as the Counter Assault Team, or CAT, whose dangerous job it is to repel ambushes on the presidential motorcade. The type of individual attracted to such work does not necessarily heed behavioral lectures from the boss; and there are roughly 100 of them in the Secret Service now, roughly twice as many as before Sept. 11, 2001, according to Secret Service officials.

Still, there’s no excuse for misconduct that puts the president at greater risk, even by a small margin, which is exactly what getting falling-down drunk the night before you’re supposed to go on duty can do. There’s no excuse for damaging the reputation of your country and disgracing your agency. To drum home that message, yet again, the Secret Service sent three agents home from the Netherlands and placed them on administrative leave; we assume tougher discipline is to follow. Yes, the agency has taken steps since Cartagena to prevent misconduct. Obviously, it’s going to have to do more.