If there’s a common theme uniting Democratic candidates for president, it’s the argument that the United States faces a rising inequality problem, one exacerbated by the concentration of power and money in the hands of a small elite.

That line of thinking has been the source of high-profile policy ideas such as a tax on wealth or Medicare-for-all. But it’s also given momentum to a wider debate about corporate consolidation and whether the rules designed to keep the free market fair are working for everyday Americans.

Sen. Amy Klobuchar (D-Minn.), a candidate for the Democratic presidential nomination, is among those calling for tougher competition rules. In an interview Tuesday, Klobuchar, the top Democrat on the Senate Judiciary antitrust subcommittee, argued that public anger over high prescription drug prices, privacy violations by tech companies and a string of megamergers shows how U.S. laws need to change.

The transcript below has been edited for length and clarity.

Does the United States have a monopoly problem?

We have a major monopoly problem. We’ve seen a 50 percent increase in mergers in the last five years, and we’ve seen now a number of trillion-dollar companies. It doesn’t mean every big company is bad; it just means we’re seeing more and more consolidation of power. The problem is, our antitrust laws haven’t attacked changes in the kinds of businesses we have.

Let’s start with the courts. You have conservative decision after conservative decision on antitrust. [Supreme Court Justices Brett M.] Kavanaugh and [Neil M.] Gorsuch have a number of opinions that are actually more conservative than where the court has been, in terms of how they interpret the [antitrust] laws.

Which industries pose the biggest antitrust problems, in your view?

First is tech. We haven’t been able to move privacy legislation for years. The second area is pharma, where literally they have three lobbyists for every member of Congress. You’re starting to see common drugs like insulin that have been around for a century, where you’ve seen prices triple or quadruple. The answer here is to pass new legislation that — when it comes to things like pharma — address “pay for delay.”

And then also do something about the antitrust laws. I have two bills: One is to increase the fees on companies that are in megamergers, so that we can better fund the Federal Trade Commission and the Justice Department. The second piece of it is to do something about the [legal] standard.

A number of antitrust critics have called for breaking up Facebook. Do you agree?

I would like to see investigations which are going on right now at the FTC of the different aspects of these monopoly companies. That’s what I’m pushing for right now, and then you look at the facts and you make a decision then. But I would love to get more competition in. And it’s going to be very hard to do that before we get major investigations and we start changing the law.

Can you reflect on the performance of the Justice Department’s antitrust division, and in particular, on the AT&T-Time Warner merger?

I agreed with them on going forward with that [lawsuit to block the deal]. I certainly didn’t agree with the reasoning being CNN. [Note: Time Warner owns CNN, a frequent target of President Trump’s criticism.]

There’s two competent people, [FTC Chairman Joseph] Simons and [Justice Department antitrust chief] Makan Delrahim. They know what they’re doing. But instead of taking this on as a general antitrust issue, which I wish this administration would do, the president actually undercuts it by using it as a political grenade. ... He’s used it as a political grab bag. That’s not how you make change in antitrust law.

Antitrust cases tend to revolve around consumer prices because they’re one of the simplest ways to show consumers have been harmed. Some argue the focus on prices excludes other theories of harm. How should the government think about that?

We need to change the laws so they’re looking at other factors, like monopsony. It is [a] choice to follow this Robert Bork, University of Chicago school — where I went to law school, by the way — approach. But it’s not like a given that that’s where the court is going to stay forever, in terms of their narrow view ...

We need to get more funding into the agencies, and we need to change the standard. That would be an appropriate thing to do.