Congressional Republicans—especially in the House—need a political war college that schools incumbents and challengers in the best way to explain, defend and attack on the issue of Medicare reform. They have to become as comfortable talking about Medicare in the coming year as they did in talking about health-care reform last year.

There needs to be preparation and self-education, followed by extensive town halls, outreach meetings, visits to senior citizen centers, and the use of every available communications tool to get the reform message across.

A good starting point is Mr. Ryan’s message from his speech at the Economic Club of Chicago that his Medicare reform package “makes no changes for those in or near retirement, and offers future generations a strengthened Medicare program they can count on, with guaranteed coverage options, less help for the wealthy, and more help for the poor and the sick.”

The populist note is especially important: When he starts receiving Medicare, Bill Gates should bear a greater share of his health-care costs than the less healthy or less wealthy.

Defense, no matter how robust, well-informed and persistent, is insufficient. Republicans must also go on offense.