From Thomas P. Miller's column in National Review:
The response of roughly half of the Senate Republicans was to co-sponsor an alternative bill offered by Senator John Chafee that included an individual mandate. And about as many Senate Republicans (with some overlap) co-sponsored another pro-mandate bill advanced by Senator Don Nickles  and essentially designed by the Heritage Foundation’s health-policy team.
But then-senator Phil Gramm, along with Bill Kristol’s Project for the Republican Future, rallied the troops. Almost all other conservative policy groups (such as the Cato Institute, the National Center for Policy Analysis, the Manhattan Institute, the Competitive Enterprise Institute, Citizens for a Sound Economy — a forerunner of FreedomWorks — and even parts of AEI) joined in, along with even stronger grassroots sentiment, against Hillarycare part I. I don’t recall running into J. D. Kleinke at any of those meetings planning how to stop the Health Security Act, or his writing any papers for, or against, the Heritage-sponsored individual-mandate alternative that by the spring of 1994 was abandoned by most Capitol Hill Republicans.