This Republican Plan simply rations health care and choice of doctor by income.What bizarre rhetoric for a US politician in one of the country's major political parties to use. Everything we buy that is not subject to government price controls, directly or indirectly, is "rationed" by income. In the vernacular, this simply means the thing in question has a price to be paid by the person who wants to consume it, as everything must in a free market. The car, the house, the soap, and the sandwich you buy are all rationed by income, or more precisely, by money. It's basic supply and demand, the most rudimentary concept in economics.
I don't follow mainstream political punditry very closely, though I've not heard it being seized on by the popular right. Maybe the Rasmussen poll from a couple of years ago finding only a very slight majority of the public saying capitalism is a better economic system than socialism means it's rhetorically trickier than I'd imagine it to be, and maybe public sentiment is in favor of shielding health care costs entirely from the individual and collectivizing them in their entirety, but Van Hollen's statement reveals a socialistic mindset if ever one did--the idea that if an individual must pay the market rate for something, that thing is being "rationed", with all the negative connotations that go along with such a word choice in contemporary America.