This is absolutely the wrong way to deal with people in the so-called center. The right conception is that they are people you want to convert to your way of thinking, not you converting to theirs. Instead of trying to moderate your way to the middle, you convince them to immoderate and tilt to the right.
You don't convert the middle by preaching doctrine. That's the point being made, not that No Child Left Behind or the Medicare drug benefit was a good thing.
You lead by example and lead people to make the conclusions that make sense. You don't go preaching the 10th Amendment. People, normal people not FReepers and other political junkies, tune out on this kind of thing.
Preach that the EPA is killing the economy. Make it real. Use concrete illustrations. Then give it a doctrine name, if you have to.

So, let me get this straight. The Tenth Amendment of U.S. Constitution* is "doctrine" that a candidate for the 2012 (that means post Tea Party America) GOP POTUS nomination should NOT be "preaching" to the electorate?!
You aren't Rich Flowry, are you?
* The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people. ... the 10th Amendment to the U.S. Constitution
“You don’t convert the middle by preaching doctrine... You lead by example and lead people to make the conclusions that make sense. You don’t go preaching the 10th Amendment... Preach that the EPA is killing the economy. Make it real. Use concrete illustrations. Then give it a doctrine name, if you have to.”
—I agree with some of your points, but I think you’re forgetting the flip-side to the 10th Amendment. Under a pure 10th Amendment view, states are allowed to experiment with the powers reserved to them (and not expressly given to the Federal government, etc.); if that means that a blue state wants to enact gay marriage or whatever social-related policies through its police powers, then under this view it has that right. If one believes the poll numbers that support for such policies is around 50/50 or so, then it why wouldn’t moderates support such a 10th perspective (once it was properly explained to them)?