While some lawmakers and wonks are busy cooking up alternatives to the controversial federal mandate requiring people to have health insurance starting in 2014, one early backer of the approach insists it remains the best way to get more people covered at the lowest cost. And, MIT economics professor Jonathan Gruber isn't just any old mandate supporter. He's an architect of Massachusetts' insurance mandate program. And he also did a little economic modeling for the Obama administration during the debate that led to the passage of last year's health overhaul. Now, in a paper released by the liberal think tank Center for American Progress, Gruber revs up his estimating machine again to argue that the leading mandate replacements, such as penalties for people who delay buying insurance, wouldn't do nearly as much to address the twin problems of coverage and cost.