STORM LAKE, Iowa (AP) — Democratic presidential contenders Elizabeth Warren and Amy Klobuchar expressed support Saturday for strengthening antitrust laws and enforcement to break up big agriculture monopolies. “You’ve got these giant corporations that are making bigger and bigger profits … and they’re putting the squeeze on family farms and small farms,” Warren said at the Heartland Forum, which was focused on rural issues.

The U.S. senator from Massachusetts called for breaking up some of the biggest farming corporations “so that they not only do not have that kind of economic power, so that they’re wiping out competition, so they’re taking all the profits for themselves … but also so that they don’t have that kind of political power.”

While supporting an antitrust approach, Klobuchar, a senator and Minnesota Democrat, also proposed putting a fee on corporate mergers to help investigate noncompetitive practices. “If we stifle competition through monopolies, we’re not just going to bring up the prices for consumers, we’re going to stifle entrepreneurship,” she said.

Targeting monopolies was a key part of the agriculture policy Warren rolled out this week, which included a handful of proposals aimed at helping family farmers compete in a market increasingly saturated by major corporations. Klobuchar and former Maryland Rep. John Delaney, another White House hopeful who attended the forum, also rolled out rural-focused policies this week.

Klobuchar announced a $1 trillion infrastructure plan that would help expand access to rural broadband and strengthen roads and bridges. Delaney offered a comprehensive rural plan that included proposals to strengthen family farmers and rural infrastructure. Other White House contenders at the forum were former Housing and Urban Development Secretary Julian Castro and Ohio Rep. Tim Ryan, who is considering launching a bid.

The attention on agricultural communities and issues is the result of a recognition that Democrats need to do more to win over rural voters, especially in places like Iowa. The state has long been a presidential battleground, but Iowa has trended more solidly Republican over the past two election cycles, a troubling sign for Democrats seeking to oust President Donald Trump.