He has good reason to believe this approach will work. When supporters hear new ideas set alongside unquestioned pillars of culture, as they did in this speech, they imagine those new ideas less as experiment and more as writ.
Casual listeners simply hear traditional language and assume that anything mixed in with it is also traditional, or at least widely accepted. The only people who would be put off by the content of this speech would be highly engaged listeners who are never going to agree with the speaker anyway.
Having presented his premise as the need for national accomplishment, and having done so in terms no one can argue with—who doesn’t want railroads, highways and schools?—he pivoted to a specific argument for a fairly specific kind of unified purpose, one that requires rules, regulation and protection from “life’s worst hazards and misfortune,” and “new responses to new challenges” cast as an alternate way to act on the principles of our founders.
Or, as a Reuters writer delicately put it, Obama spoke “in more specific terms than is customary.” And to make it go down well, he wrapped it in founders’ bunting.