PRINCETON, NJ -- Hillary Clinton is currently the best known and best liked of 16 potential 2016 presidential candidates tested in a July 7-10 Gallup poll, due to her 91% familiarity score and +19 net favorable rating. The net favorable is based on her 55% favorable and 36% unfavorable ratings.

In the graph seen above, those potential candidates in the upper-right quadrant are viewed more positively than negatively by Americans and have above average familiarity. The further candidates in that quadrant are away from the intersecting lines, the higher their scores are on both dimensions. The graph clearly shows Clinton's strong image positioning relative to other candidates at the moment for the general election. Gallup will report on candidate images among rank-and-file Republicans and Democrats in the coming days to see how the 2016 hopefuls stack up for their respective party's nomination.

Those potential candidates in the other three quadrants have weaknesses in familiarity, favorability, or both. Those in the lower-right quadrant are better known but less well liked, and must work to change people's opinions about them. Those in the upper-left quadrant are better liked but less well known, and their challenge lies more in becoming nationally known figures.

Huckabee May Have Slight Edge in GOP Field for General Election

Former Arkansas governor and current talk show host Mike Huckabee is arguably in a slightly better position image-wise among the national adult population than other potential Republican presidential candidates. His +12 net favorable rating edges out Kentucky Sen. Rand Paul's +9 for the highest among Republican candidates. Huckabee's 54% familiarity score trails those for New Jersey Gov. Chris Christie (65%) and former Florida Gov. Jeb Bush (65%), but is above the 52% average for the 11 Republicans measured in the poll. Christie's and Bush's net favorable ratings are among the lowest.

Florida Sen. Marco Rubio has an above average +8 net favorable among national adults, but lags other Republican candidates with 46% familiarity. Texas Gov. Rick Perry and Wisconsin Rep. Paul Ryan are slightly above average in terms of both of favorability and familiarity.

Louisiana Gov. Bobby Jindal has the same +6 net favorability as Perry and Ryan, but is among the least well-known Republicans included in the poll with 38% familiarity. Texas Sen. Ted Cruz, Wisconsin Gov. Scott Walker, and former Pennsylvania Sen. Rick Santorum are below average in both favorability and familiarity, with Santorum viewed more negatively than positively.

Biden Is Well-Known, Not Well-Liked

Two of the five Democrats included in the poll have net negative favorable ratings -- Vice President Joe Biden and Maryland Gov. Martin O'Malley. O'Malley is the least known potential candidate in the survey, with 83% of Americans not having an opinion of him. Biden's net negative favorable rating could be more troubling in terms of his 2016 prospects, as 80% of Americans have an opinion of him, second only to Clinton among the 16 candidates in the poll.

Americans are slightly more likely to have a positive than negative view of Massachusetts Sen. Elizabeth Warren (21% favorable, 17% unfavorable) and New York Gov. Andrew Cuomo (27% favorable, 24% unfavorable). Cuomo is the better known of those two, but still has below average familiarity.

Perry, Christie, Cruz Images Recovering

The candidates with net negative favorable ratings can take some solace in knowing that Americans are quick to forgive -- or perhaps to forget -- when politicians do things that reflect negatively on them. Three of the potential candidates in the current survey -- Perry, Christie, and Cruz -- were rated much more negatively than positively the last time Gallup asked about them, and all are back to at least a slightly more positive than negative favorable rating.

Perry's recovery may be the most impressive. When Gallup last measured him in December 2011, with his 2012 presidential campaign sputtering due to poor debate performances, he had a net favorable rating of -28 (27% favorable, 55% unfavorable). His familiarity scores are down since then, from 82% to 58%, but those able to rate him are now more positive than negative.

Christie became a prominent and well-regarded national figure known for taking on the Democratic legislature in New Jersey and for his response to Superstorm Sandy. In June 2013 he had a +32 net favorable rating. The "Bridgegate" scandal last fall sent Christie's image plummeting, to a net -9 favorable rating earlier this year, before improving to +1 in the current poll.

Cruz, a central figure in the government shutdown last fall, had a net favorable rating of -10 in an October 2013 Gallup poll. Eight months later, his net favorable rating is back to +2.

Biden is the only potential candidate whose image is notably worse than the last time Gallup measured him, with his net favorable rating slipping to -4 from +4 in February.

Implications

The viability of a candidate's chances depends both on voters knowing who the candidate is, but also on voters having a positive impression of the candidate. Candidates usually become better known over the course of a campaign, but those who are better known at the outset have an advantage in that they don't have to work as hard to attract attention to, or raise money for, their campaigns. On the other hand, those who are well-known may have more difficulty improving their image during a campaign.

Although Clinton is the best-liked potential candidate in the poll -- 18 months before the first primaries or caucuses -- her favorable ratings are lower now than when she was secretary of state. They are, however, better than in July 2006, a year-and-a-half before the 2008 primaries, when she had a +6 net favorable rating (50% favorable, 44% unfavorable), before running a competitive but ultimately unsuccessful bid for the Democratic presidential nomination.

So while Clinton's image has lost some of its luster as she has moved from a less overtly political role as secretary of state to her current role as a book author and potential presidential candidate, she is in an arguably stronger position with the public now than she was before her 2008 presidential campaign.

Survey Methods

Results for this Gallup poll are based on telephone interviews conducted July 7-10, 2014, with a random sample of 1,013 adults, aged 18 and older, living in all 50 U.S. states and the District of Columbia.

For results based on the total sample of national adults, the margin of sampling error is ±4 percentage points at the 95% confidence level.

Interviews are conducted with respondents on landline telephones and cellular phones, with interviews conducted in Spanish for respondents who are primarily Spanish-speaking. Each sample of national adults includes a minimum quota of 50% cellphone respondents and 50% landline respondents, with additional minimum quotas by time zone within region. Landline and cellular telephone numbers are selected using random-digit-dial methods. Landline respondents are chosen at random within each household on the basis of which member had the most recent birthday.

Samples are weighted to correct for unequal selection probability, nonresponse, and double coverage of landline and cell users in the two sampling frames. They are also weighted to match the national demographics of gender, age, race, Hispanic ethnicity, education, region, population density, and phone status (cellphone only/landline only/both, and cellphone mostly). Demographic weighting targets are based on the most recent Current Population Survey figures for the aged 18 and older U.S. population. Phone status targets are based on the most recent National Health Interview Survey. Population density targets are based on the most recent U.S. census. All reported margins of sampling error include the computed design effects for weighting.

In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.

View survey methodology, complete question responses, and trends.

For more details on Gallup's polling methodology, visit www.gallup.com.