There's a cliche you've all heard before: fortune favors the bold. It's not quite true, as the bold can end up a smoking crater in the wrong situation, but it holds some truth, at least in politics. Big Ideas get people interested, as does the willingness to act boldly and confidently in your beliefs and ideas. Combine the two (bold support of a Big Idea), and it has to be appallingly bad in order to lose support.
(That's the Bush administration in a nutshell: Big Ideas, expressed boldly, that are so badly thought out that they end up alienating even the most frightened of Security Moms. Pity that the people who end up cratering aren't the Idea men.)
Rick Perlstein, when speaking to the crypto-DINO DLC, argued that social security is one of those Big Ideas (he calls them Superjumbos, but the name doesn't matter), and that nationalized health insurance could be another one. He shows how frightened the Republicans were of Clinton's health care bill going through, because it would cement the Dem's "defenders of the middle class against the depradations of robber barons" trope.
The Republicans know that the only way they can credibly present themselves as "populist" is if they can paint the Democrats as supporting an atheistic and immoral "cultural elite" while simultaneously blurring the lines between the parties on economic issues. Health care would redraw that line, and the Republicans don't want that to happen. Since there's only two viable parties, it stands to reason that anything that the Republicans are politically worried about is probably good for the Dems.
Considering the Republicans nowadays, it's probably good policy too.
The biggest problem that Perlstein has is that he was speaking to the, um, Democratic Leadership Council. National health care is not really part of their platform, which appears to be trying to out-Republican the Republicans and take shots at their own party members. They're the champions of the nice-sounding but utterly bankrupt "socially progressive and fiscally conservative" perspective--usually civil libertarians who forget that taxes pay for things--and are not going to get behind this.
It's a Big Idea, but the DLC isn't the home of Big Ideas, it's the home of "triangulating" small thinkers who wouldn't know "bold" if it kicked them in the teeth. They would scream "EXTREMIST" if they actually did recognize someone being bold. That is why they can't stop losing.
(Is it hypocritical to take shots at them for taking shots at others? Perhaps, but there's a distinction between punishing boldness and identifying "centrists" who attack those who don't support pathetically obvious weakness.)
Edit: Perlstein, in comments, said that the speech wasn't made to the DLC, but to "powerful Democrats". My apologies to Perlstein, if not the DLC. Their presence and their attitude remains the key reason why the health care system Perlstein is advocating is unlikely at best.