It’s simpler than that. Conservatism works. Small government, federalism, strong national defense, moral behavior, freedom, personal responsibility—these are smart and effective ways for human societies to maximize individual success and happiness. These principles don’t yield results that are good only for conservatives—they yield results that benefit everyone (save some entrenched interests).
Conservative politicians need to be good communicators, and they need to win over non-conservatives—but *not* by pretending not to be conservative, but by showing non-conservatives how they, too, will benefit from conservative policies.