(1) Clinton has been declared the numerical victor (albeit by a razor thin margin). (2) Sanders and his campaign rightly sense a victory in that they closed the gap from polls overwhelmingly favoring Clinton to a 50-50 result in the Iowa caucuses. (3) The third win was for what Sanders originally claimed - for his ideas. Because of the fundamental progressive strength of those ideas, Clinton was forced to carry a more progressive banner. And that will likely continue tus sharpening the contrast between whichever Democratic candidate eventually prevails and the Republican opponent in the general election.
I don't think anyone else would spin it quite that way, but the closest would be John Nichols writing at The Nation. Here are Nichols' concluding remarks.
Sanders leaves Iowa as what he has always been: an economic populist who is challenging a broken status quo.
Clinton leaves Iowa as an evolving candidate. That’s good. She is evolving toward a populism that—should she win her party’s nomination—will make her a stronger fall contender.
As the Iowa campaign closed, Clinton seemed to be enjoying the chance to let rip in front of cheering crowds. “We can’t afford to make a mistake,” she told 2,600 people at a high school in Des Moines on Sunday night. “I want you to think for a minute about what the Republican candidates are talking about as they make their final appeals. They want to rip away the progress we’ve made. They want to rip back rights that have been extended. They want to go back to trickle-down economics that wrecked our economy.”
That’s a stronger message than Clinton brought to Iowa, a more progressive and populist message.
The competition from Bernie Sanders has emboldened Hillary Clinton. There’s a political revolution going on. How it ends, we do not know. But Iowa has started something good for both Bernie Sanders and Hillary Clinton.