From The Nation editorial endorsement

Barack Obama picked up the endorsement of The Nation magazine, which said in part:

The question of who can best build popular support for a progressive governing agenda is related to, but distinct from, the question of electability. Given a certain ceiling on Clinton's appeal (due largely to years of unhinged attacks from the "vast right-wing conspiracy"), her campaign seems well prepared to run a 50 percent + 1 campaign, a rerun of 2004 but with a state or two switching columns: Florida, maybe, or Ohio. Obama is aiming for something bigger: a landmark sea-change election, with the kind of high favorability and approval ratings that can drive an agenda forward.

Why should we think he can do it? The short answer is that Obama is simply one of the most talented and appealing politicians in recent memory. Perhaps the most. Pollster.com shows a series of polls taken in the Democratic campaign. The graphs plotting national polling numbers as well as those in the first four states show a remarkably consistent pattern. Hillary Clinton starts out with either a modest or, more commonly, a massive lead, owing to her superior name recognition and the popularity of the Clinton brand. As the campaign goes forward Clinton's support either climbs slowly, plateaus or dips. But as the actual contest approaches, and voters start paying attention, Obama's support suddenly begins to grow exponentially.

In addition to persuading those who already vote, Obama has also delivered on one of the hoariest promises in politics: to bring in new voters (especially the young). It's a phenomenon that, if it were to continue with him as nominee, could completely alter the electoral math. Young people are by far the most progressive voters of any age cohort, and they overwhelmingly favor Barack Obama by stunning margins. Their enthusiasm has translated into massive increases in youth turnout in the early contests.

Finally, there's the question of coattails. In many senses there's less difference between the two presidential candidates than there is between a Senate with fifty-one Democrats and one with fifty-six. No Democratic presidential candidate is going to carry, say, Mississippi or Nebraska, but many Democrats in those states fear that the ingrained Clinton hatred would rally the GOP base and/or depress turnout, hurting down-ticket candidates. Over the past few weeks a series of prominent red-state Democrats, most notably Ben Nelson, Kent Conrad and Kansas Governor Kathleen Sebelius, have endorsed Obama. When I asked a Democratic Congressional candidate in the Deep South who he preferred at the top of the ticket, he didn't hesitate: "Obama is absolutely the better candidate. Hillary brings a lot of sting; he takes some sting out of them."

For other endorsements, news and post-debate chatter: American Dash.