WASHINGTON - The 2016 Republican presidential nominating battle is shaping up as the most wide-open in a generation, with a new Washington Post-ABC News poll showing five prospective candidates within 4 percentage points of one another at the top and a half-dozen more in the mix.

The picture is very different on the Democratic side, where former Secretary of State Hillary Rodham Clinton is the clear front-runner. In a hypothetical matchup, Clinton leads former Florida governor Jeb Bush - seen by many GOP establishment figures as the party's strongest general-election candidate - 53 percent to 41 percent.

Clinton's commanding position is fueled by large leads over Bush with female, non-white, and young voters. The poll found that neither Clinton nor Bush appears to be weighed down by a dynastic family name. Sixty-six percent of all Americans say they view the Clinton family favorably, while 54 percent have a favorable opinion of the Bushes.

In the GOP primary contest, which is only beginning to take shape as prospective candidates test messages and assemble national networks, nobody has emerged as an anchor in the field.

Among Republican and GOP-leaning independents, Bush and Sen. Rand Paul of Kentucky share the top ranking at 14 percent, though with a statistically insignificant lead. Former Arkansas Gov. Mike Huckabee runs third at 13 percent, followed by Rep. Paul Ryan of Wisconsin at 11 percent and New Jersey Gov. Christie at 10 percent.

Sens. Ted Cruz of Texas and Marco Rubio of Florida, Wisconsin Gov. Scott Walker and Texas Gov. Rick Perry follow close behind, while support for Louisiana Gov. Bobby Jindal and Ohio Gov. John Kasich stands in the low single digits.

Among Republicans who identify as "very conservative," Huckabee is the clear leader, favored by 21 percent. A former Baptist minister whose faith has helped propel his political career, Huckabee is especially strong among white evangelical Protestants, winning 22 percent of that group.

Christie, who has struggled to rebound from the George Washington Bridge traffic scandal, does not lead among any demographic or ideological group.

The Post-ABC poll was conducted Thursday to Sunday among a random national sample of 1,000 adults, including interviews on conventional telephones and with cellphone-only respondents. The margin of sampling error for overall results and among the 855 registered voters interviewed is plus or minus 3.5 percentage points.