As far as I know, I've been a good Democrat for quite some time now, so let's see if he could "work with" me as a representative good Democrat. Is he going to support reproductive choice, gay marriage, Social Security, Medicare + a solid medical care program for everyone, investment in infrastructure, investment in job creation, appropriate regulation of the financial industry, enforcing environmental regulations on industry thus protecting the national resources of air, water, and soil, taxing the individuals and corporations not now paying income tax at their assigned rate through loopholes (if corporations want to have the rights of individuals--which the Supreme Court gave them--they can damn well pay taxes like individuals), investment in education (especially to free quality public education for all with science and not religion in charge), commitment to long-term sustainable environmental habits...etc...???
Oh. Surprise. He's not, actually, as centrist as he claims. By "good" Democrats he means the most conservative Democrats he can drag up and those passive, beaten-down Democrats who don't dare raise their voices..
Well, I could work with "good" Republicans (and there used to be good Republicans. I even voted for some of them back down the line.) But you see, Romney does not meet my definition of a good Republican any more than I meet his definition of a good Democrat.
Ritual disclaimer. Yes, Virginia, there are worse Republicans than Romney. Perry, for instance. That does not make Romney "good."