“So you can see how this is useful to each other over time,” he continued. “No one else has this infrastructure. We’re very excited about doing it.”

The Center for Public Integrity obtained a previously unpublished audio recording of the meeting, which focused on the Kochs’ higher education funding strategy, from liberal activists who produce The Undercurrent, an online video program.

Higher education has become a top Koch priority in recent years. And their funding — as well as pushback against it — is increasing.

During 2013, a pair of private charitable foundations Charles Koch leads and personally bankrolls combined to spread more than $19.3 million across 210 college campuses in 46 states and the District of Columbia, according to a Center for Public Integrity analysis of Internal Revenue Service tax filings.

That represents a significant increase from the $12.7 million the Koch foundations distributed among 163 college campuses in 41 states and the District of Columbia during 2012. It’s also exponentially more than what the Koch foundations together spent directly on higher education a decade ago.

The Center for Public Integrity reviewed hundreds of private documents, emails and audio recordings that, along with interviews with more than 75 college officials, professors, students and others, indicate the Koch brothers’ spending on higher education is now a critical part of their broader campaign to infuse politics and government with free-market principles.

The Charles Koch Foundation executives declined to be interviewed individually. Trice Jacobson, a foundation spokesperson, instead provided a statement that she said “captures what we all hope to share for this piece.”

“Like many charities, the Charles Koch Foundation recognizes the importance of supporting a diversity of ideas so scholars and students can continue to push the frontiers of knowledge and help people discover new and better ways to live fulfilling lives,” the statement read. “Our giving has expanded to support new research and programs on critical issues ranging from criminal justice reform to corporate welfare.”

In a separate statement of its “academic giving principles,” the Charles Koch Foundation asserts that it is “committed to advancing a marketplace of ideas and supporting a ‘Republic of Science’ where scholarship is free, open and subject to rigorous and honest intellectual challenge.”

It also notes that scholars and students “who are free to teach, learn, research, speak, critique and receive support for their work without interference” are in the “best position to discover the advances that will help improve well-being.