Former secretary of state Hillary Rodham Clinton speaks during the 2015 Iowa Democratic Wing Ding at the Surf Ballroom in Clear Lake, Iowa, on Friday, Aug. 14, 2015. (Photo by Melina Mara/The Washington Post)

It's been a bad summer for Hillary Rodham Clinton's polling numbers, and a new Washington Post-ABC News poll brings additional bad news for her brand.

But it also shows something else: She continues to be popular among a broad coalition of Democrats, and is still better liked than GOP heavyweights Donald Trump and Jeb Bush with the public at large.

Let's start with the bad news for Clinton. Fully, 53 percent have an unfavorable impression of her, the highest since April 2008 in Post-ABC surveys. That mark is eight percentage points higher than in July, though not as far from a Post-ABC poll in late May (49 percent). Intense views also run clearly against Clinton, with almost twice as many having a "strongly unfavorable" view of her (39 percent) as "strongly favorable" (21 percent).

Concerns about Clinton's falling popularity have fed uncertainty among Democrats about her electability, as well as speculation that Vice President Biden will challenge her for the Democratic nod. But the Post-ABC poll finds Biden's image before starting a campaign is far from stellar, at 46 percent favorable to 46 percent unfavorable.

What's more, among fellow Democrats, Clinton boasts a higher favorability rating of 80 percent to Biden's 70 percent. Both Biden and Clinton garner favorable ratings above 80 percent among liberal Democrats, but among moderate and conservative Democrats, Clinton's 3-to-1 positive ratio outstrips Biden's 2-to-1. Clinton is also more popular with Democrats than Donald Trump or Jeb Bush among their base; each candidate's favorable ratings among Republicans stand below 60 percent.

Biden's edge in popularity over Clinton is due to better ratings among independents and Republicans. Fully 26 percent of Republicans report a favorable view of him -- similar to Clinton's 31 percent favorable rating in January before she entered the presidential race. After four months of campaigning, though, just 13 percent of Republicans now give Clinton positive marks -- a drop Biden could also suffer if he joins the presidential fray.

Clinton is also significantly stronger than Biden among African Americans and Hispanics, at 79 and 68 percent favorable, respectively. For the slightly lesser-known Biden, favorable ratings stand at 67 percent among blacks and 49 percent among Hispanics.

Biden's clearest advantage over Clinton is among political independents. The same share rate each candidate as "favorable," but 59 percent see Clinton unfavorably, compared with 50 percent for Biden (more report "no opinion" of Biden).

If Biden's on-the-sidelines popularity doesn't appear too threatening to Clinton, neither do two prominent GOP hopefuls. Clinton continues to be more popular than Trump (37 percent favorable to 59 percent unfavorable) or Bush (38/55).

Clinton's image is surprisingly weak among some core groups that helped elect Barack Obama, including younger Americans and women. Her ratings are 48 percent favorable to 51 percent unfavorable among women. Biden draws a similar 45 percent favorable-45 percent unfavorable split among women.

Among adults aged 18-to-39, Clinton splits 47 percent favorable to 50 percent unfavorable. Biden tilts slightly more positive at 46 favorable to 42 percent unfavorable.

Trump and Clinton have one thing in common: They both have a similar levels of intense opposition. For Clinton, 39 percent rate her strongly unfavorably, nearly matching Trump's 43 percent strong unfavorable rating.

Trump’s strong unfavorable marks spike in groups the Republican Party has been hoping to reach out to in presidential elections – Hispanic and African Americans. More than eight in 10 in each group rate him unfavorably, and 68 percent of each group says they have a “strongly unfavorable” impression of the businessman.'

Bush has fewer strong opponents, with 29 percent ratings him strongly unfavorable. And he draws a respectable level of popularity among Hispanics, with 43 percent favorable to 46 percent unfavorable.

For Bush, political independents represent a weak point overall and relative to Trump. The balance of opinion among independents for Trump (41/54 favorable/unfavorable) is better than Bush's (33/58). They both tilt more negative than positive, but Trump's ratings have moved up since July, from a margin of negative-23 to -13 currently. Bush has moved in the opposite direction among independents since July, from -13 to a wider -25.

The Post-ABC poll was conducted August 26-30, 2015 among a random national sample of 1,005 adults, interviewed on conventional and cellular phones. The results from the full survey have a margin of sampling error of plus or minus 3.5 percentage points. See full question wording and methodology