At least Romney talked taxes when he signed Romneycare into law:

Our experience also demonstrates that getting every citizen insured doesn’t have to break the bank. First, we established incentives for those who were uninsured to buy insurance. Using tax penalties, as we did, or tax credits, as others have proposed, encourages “free riders” to take responsibility for themselves rather than pass their medical costs on to others. This doesn’t cost the government a single dollar. Second, we helped pay for our new program by ending an old one — something government should do more often. The federal government sends an estimated $42 billion to hospitals that care for the poor: Use those funds instead to help the poor buy private insurance, as we did.

In contrast, Congress and President Obama explicitly avoided using the word tax--until, that is, they finally had to argue their case in court.