Can the government play a stronger role in regulating the business of online tickets for concerts and other events?

When lawmakers and federal agencies have considered that question, they have tended to focus on fairness to consumers. In June, for example, the Federal Trade Commission held an industry conference looking at topics like the surcharges tacked on by companies like Ticketmaster and StubHub.

This week, two United States senators went further by asking the Justice Department to investigate the state of competition in the ticketing business, and to extend a regulatory agreement with Live Nation Entertainment, the industry behemoth that owns Ticketmaster.

In a letter to Makan Delrahim, the assistant attorney general in charge of antitrust, the senators, Richard Blumenthal of Connecticut and Amy Klobuchar of Minnesota — both Democrats — called the ticket industry “broken” and complained of “exorbitant fees and inadequate disclosures” in the ticket buying process.