Peter Beinart describes very accurately what has happened to the democrats.

Barack Obama is a representative of the younger, more ideologically-committed, much more naive generation of left-wing democrats, typical of that party’s radical base. He’s the type of democrat who is too young to have seen George McGovern lose 49 states or see Jimmy Carter shredded by Ronald Reagan.

[A] generation of Democrats, which includes Al From, Mark Penn, Joe Lieberman, William Galston, Elaine Kamarck, Dick Morris, Ed Koch, Jane Harman, Evan Bayh, and to some extent Bill and Hillary Clinton, being a liberal is like walking past a bear. Move cautiously and reassuringly and the bear will purr contentedly. But make any sudden or threatening gestures, and you’ll be mauled because, fundamentally, the bear distrusts liberals. As Galston and Kamarck wrote in their famed 1989 essay “The Politics of Evasion”—a document that helped define the “don’t scare the bear” wing of the party—Democrats can pass liberal programs “but these programs must be shaped and defended within an inhospitable ideological climate.” To pretend that the American people are liberal at heart is to evade political reality, with devastating results.

By the late 1990s, “don’t scare the bear” Democrats pretty much dominated Washington. But in the Bush years, a new faction began to emerge. These Democrats were mostly newer to politics. They had never seen a McGovern or Mondale mauled for being too far to the left. What they had seen was the post-1994 Bill Clinton, who shied away from ambitious liberal reform. And they had seen the Iraq War, which DLC types largely supported, partly out of fear that opposing it would allow Republicans to paint Democrats as soft on defense.

By 2003, this new group of Democrats was angry as hell. The Iraq War, which party elders had mostly backed, was proving a disaster, and to make matters worse, Republicans were clobbering Democrats as weak anyway. So these Democrats began fashioning a different theory: Perhaps the problem wasn’t that Democrats looked weak because they were too liberal, perhaps the problem was that Democrats looked weak because they didn’t stand up for what they really believed. In 2005, the historian Rick Pearlstein—who became something of a hero to these folks—published a book entitled The Stock Ticker and the Super Jumbo. Republicans, he argued, were like Boeing: a company that persevered in building a super jumbo airplane even when the market was bad, and thus built a dominant brand. Democrats were like the stock ticker, constantly shifting with the public mood and thus winning momentary victories but failing to build a brand people could identify with.

To change, Perlstein argued, “Democrats need to make commitments, or a network of commitments, that do not waver from election to election.” They must stick with them “even if they don’t succeed” at any given moment because doing unpopular things because you believe in them convinces Americans that you have core beliefs, which in the long term strengthens your brand. …

When Scott Brown won his Senate seat, he made Obama choose. On the one hand, he handed the White House an excuse to abandon comprehensive reform and return to the incremental, small-bore approach that Clinton pursued after 1994. The Brown victory, in fact, seemed to illustrate the “don’t scare the bear” theory perfectly. Obama had passed the stimulus and bailed out the banks and taken over part of the auto industry and for the American people, it was too much liberal activism too fast. Polls not only showed Americans turning against Obama’s health care bill, they showed them turning against big government more generally. Continuing to pursue comprehensive reform in this inhospitable environment, warned former Carter pollster Patrick Caddell and former Clinton pollster Douglas Schoen, in language that echoed “the Politics of Evasion,” would bring political calamity. “Wishing, praying or pretending” that the American people support health care reform more than they do, they insisted, “will not change these outcomes.”

Superjumbo Democrats, by contrast, argued that the public wasn’t so much anti-reform as they were anti-the legislative process that had produced reform. But more fundamentally, they argued that the American people would respect Democrats for not backing down in the face of adversity. The party might still lose seats this fall, but over time health care reform would prove popular, and the party’s willingness to fight for it would strengthen the Democratic brand.

Why exactly Obama—advised by David Axelrod, Rahm Emmanuel and Valerie Jarrett—decided to double down on health care remains unclear. But it’s a good bet that President Hillary Clinton—advised by Mark Penn—would have acted differently. And in acting the way he did, Obama has turned himself into a superjumbo Democrat. For the foreseeable future, he has forfeited any chance of bridging the red-blue divide. Prominent Republicans have already announced that if Democrats try to pass health care via reconciliation, they will not work across the aisle to pass anything major this year. Conversely, Obama has cemented his bond with the netroots. It doesn’t really matter that the health care reform bill he is fighting for isn’t particularly left-wing. For the netroots, a politicians’ ideological purity has always been less important than his willingness to resist pressure from the other side, which is exactly what Obama has just done.

Whether health care reform passes or not, Obama has embraced polarization over triangulation. He has chosen Karl Rove’s politics of base mobilization over Dick Morris’s politics of crossover appeal, with consequences not merely for how he campaigns for Democrats in 2010, but for he campaigns for himself in 2012. And that’s a disaster for “don’t scare the bear” Democrats whether Obamacare passes or not. The reason is that the DLC wing of the party is much more top-down than the MoveOn wing. It has always wielded influence primarily through elected leaders rather than grassroots activists. But today, Obama is the only leader in the Democratic Party who really matters. As the retirement of Evan Bayh illustrates, there are few nationally prominent DLC-aligned politicians left. (The one person who could have rallied that faction of the party against Obama is now his secretary of state). The DLC wing’s best hope for relevance, therefore, was that Obama himself would restrain the party’s base, that his White House would nurture a new generation of centrist candidates.

That hope is now gone. From top to bottom, Democrats have decided to bet the party’s future on the belief that Americans prefer bold liberals to cautious ones. Now it’s up to the bear.