Greg Sargent dug a little deeper into the latest Washington Poll/ABC News poll, which was released today. As John noted earlier today, this poll is especially bad for Obama among independents. But, that’s not the real story, as far as I’m concerned. Greg learned more from the Post’s polling analyst Jennifer Agiesta about the numbers for Democrats and liberals. Those results show a growing problem for Obama with his base, which includes many of us:

The numbers tell the story: In three key cases where Obama has dropped significantly, he’s also dropped by sizable margins among Dems and liberals. Let’s take the major findings driving the discussion today, and compare them with his drop among Dems and libs:

* The WaPo poll found that “49 percent now express confidence that Obama will make the right decisions for the country, down from 60 percent at the 100-day mark in his presidency.”

On that question, among liberals, Obama has dropped a surprising 12 points, from 90% to 78%, in the same time period. Among Dems, he’s dropped eight points, from 90% to 82%.

* The WaPo poll found that “forty-nine percent now say they think he will be able to spearhead significant improvements in the system, down nearly 20 percentage points from before he took office.”

On that question, among Dems, Obama has fallen a surprising 11 points during that time period, from 90% to 79%. Among liberals it was even steeper: A drop of 13 points, from 84% to 71%. (This could also partly be a referendum on Congress, but it’s still suggestive.)

* The WaPo poll also found a steep drop in approval of Obama’s handling of health care, which now stands at 46%, down 11 points from 57% in April.

But guess what: The drop during that time period was the same among liberals: Down 11 points, from 81% in April to 70% now. Among Dems overall, Obama fell six points, from 83% to 77%.

WaPo polling analyst Agiesta cautioned that independents were likely a greater factor, but she said Obama’s problems among Dems and liberals were clearly playing a key role: “This is the first sign that something is going wrong with his base.”