The New Republic is up for sale. Facebook cofounder Chris Hughes, who bought the century-old "in-flight magazine of Air Force One" in 2012, has apparently found out that running a media business takes more than enthusiasm and deep pockets.

"After investing a great deal of time, energy, and over $20 million, I have come to the conclusion that it is time for new leadership and vision at The New Republic," he wrote in a letter to the staff posted on Medium today.

When Hughes purchased the magazine in 2012, he promised to "aggressively adapt to the newest information technologies without sacrificing our commitment to serious journalism" while also supporting the money-hemorrhaging magazine financially.

In 2014, however, Hughes' commitment came under fire after his efforts to remake the business led to the resignations of two top editors, leading to a mass exodus of editorial staffers and contributors. At the time, CEO Guy Vidra said TNR was transitioning from a century-old magazine to a "vertically integrated digital media company." The magazine's print publication schedule was cut from 20 issues a year to 10, and its headquarters was relocated from Washington, D.C., to New York City.

For Hughes, transitioning TNR into a digital powerhouse proved to be a greater challenge than he expected. "I will be the first to admit that when I took on this challenge nearly four years ago, I underestimated the difficulty of transitioning an old and traditional institution into a digital media company in today’s quickly evolving climate," Hughes wrote today. "The unanswered question for The New Republic remains: can it find a sustainable business model that will power its journalism in the decades to come?"