That is the hard part.
I can't tell for sure if you're agreeing with me on the runway-to-orbit that I'm pushing, or the Nuclear rocket you're talking about. But if it's runway-to-orbit, the way to promote it is to let Rutan and his buddies keep on flying higher and faster and getting headlines. At some point a commercial and/or government critical mass of opinion will develop and we'll do it.
Having SpaceShipOne in the Air and Space Museum down the street from the Congress will help too.
The nuke rocket is a cool engineering idea, but I just can't ever see the nimbys (or the not-over-my-heads) allowing it to happen. We can't even get permission to cut down diseased or half burnt up trees without lawsuits for years, so I can't ever see such a rocket being built for generations. At least until the population gets an entirely different attitude about nuclear.
I was talking about the runway-to-orbit air-breathing engine design.
The problem I see is Rutan isn't proposing an air-breathing engine design, nor has he ever proposed one. The Roton rocket was sort of the same idea, but even he couldn't get it to work.
I'm not saying that an air-breathing engine to LEO can't work, I know it can, but I think it will take 10 to 30 years of steady, intense, direct engineering to get us there, and nobody that I have seen is even starting in that direction.
I still think that my idea of a tax check-off for direct funding of either NASA or private industry "Prizes" for development is the best way to go.