There’s been a lot of talk about think tanks of late (and that doesn’t happen too often), spurred by the goings on at Cato and the Koch brothers’ bid to secure control over the Cato board, apparently to advance their partisan political agenda. Much of the concern has come from the right. Last week Cato staffer Julian Sanchez offered what he called a pre-resignation letter should the Kochs gain control. Sanchez made clear he loves his job and seems to consider getting to work at Cato a privilege. What he feels he would give up staying on under a Koch-controlled regime, however, is something more valuable: his academic freedom.

What disturbs Sanchez is the prospect of abandoning analysis for advocacy—swapping the institutional credibility built on producing consistent ideas and policies (regardless of what you think of them) for the power politics of electoral hectoring—starting with answers rather than questions.

Tevi Troy has written of the proliferation of newer think tanks that segment the marketplace of ideas along ideological lines. These recent entries tend to be more narrowly focused substantively, and more tactically focused on the near term. Perhaps as a consequence, they have become more predictable in their positions, sometimes at the expense of the issues they are willing to address, and what they will say about them. This seems to be the unfortunate path the Koch brothers want to take.

Mr. Troy notes that this is some distance from the original notion of think tanks, which was to produce creative, arguably groundbreaking, thinking and workable solutions to intractable issues. One of the relatively few progressives to write about the Cato doings, Ezra Klein, notes that Cato today can influence policy and governance in ways that can’t be bought. The Koch brothers, if successful in moving Cato into electoral advocacy, will have traded down.

I have the honor of directing one of those old school think tanks that traffics in ideas, The Century Foundation. It was founded over 90 years ago by a progressive Republican, and successful businessman, Edward Filene. Like the founders of Cato, Filene had an impatience to solve problems of public policy. He was suspicious of the wealthy deciding what kind of democracy was the best for the rest of us, and he was relentlessly creative in helping working Americans get a leg up economically. He was one of the least ideologically nostalgic policy wonks whose thoughts I’ve ever encountered. Yesterday’s solutions were, well, yesterday. He didn’t pen FDR’s phrase about “bold, persistent experimentation,” but he could have (he was a key FDR ally).

We’ve been looking carefully recently at Century’s archives. Flipping though the onionskin files, what I see is a clear through-line of progressive ideology and also a riot of different ways in which policy analysis found progressive expression. The values were predictable, but where the evidence led you was not.

We try to do the same today. It’s not surprising the libertarian Mr. Sanchez works at Cato. I don’t think colleagues find it surprising that Century’s fellows work here. But I do hope, like Mr. Sanchez, that we surprise them from time to time (here, for instance) with our arguments and analytics, and that Century colleagues appreciate the almost athletic challenge of breaking the mold here and there.

The Koch brothers portray themselves as defenders of free markets. I hope that at Cato, that will continue to include a commitment to a free marketplace of ideas.