Poll: Clinton surges to double-digit national lead over Trump

Support for presumptive Republican nominee Donald Trump has plunged, as Hillary Clinton opens up a 12-point advantage over her GOP rival, according to a new poll out Sunday.

An ABC News/Washington Post survey shows Clinton with 51 percent of support among registered voters nationally, up from 44 percent since the poll was last conducted in mid-May. That's compared to Trump, who now has 39 percent of support -- a seven-point drop from his May numbers.

Adding in third-party candidates like the Libertarians' Gary Johnson and the Green party's Jill Stein moves the needle very little. Clinton still has a ten-point lead over Trump, 47 percent to 37 percent, while Johnson garners seven percent of the vote and Stein has three percent.

Overall, nearly two-thirds of voters believe Trump isn't qualified to be president: 64 percent think this of the real estate mogul, compared to the 37 percent of voters that believe Clinton is unqualified.

One factor in Trump's decline in public opinion is his perceived bias against minorities. The survey finds that voters believe the business mogul is unfairly biased against groups like women, minorities, and Muslims: 66 percent think so, compared to 29 percent that don't. Sixty-eight percent believe his comments about the Hispanic judge overseeing a Trump University lawsuit in California were racist, compared to 28 percent that don't -- while 85 percent say it was inappropriate, regardless of any racist intent.

Recent events have also fueled negative opinions about the billionaire candidate. On the mass shooting in Orlando, Florida, voters believed Clinton did a better job in her response, 46 percent to the 28 percent who thought Trump did.

Another poll released Sunday, conducted by NBC News/ The Wall Street Journal, found a closer gap between Clinton and Trump in a head-to-head matchup for the general election.

Forty-six percent of registered voters throw their support with Clinton, while 41 percent back Trump. With third-party candidates factored in, Clinton's lead narrows to just one percentage point: Clinton has 39 percent, Trump has 38 percent, Johnson has ten percent, and Stein has six percent.

The ABC/Washington Post poll was conducted June 20-23 among 1,001 registered adult voters. The margin of error is 3.5 percentage points. The NBC/WSJ poll was conducted June 19-23 among 1,000 registered voters, with the survey's margin of error coming in at 3.1 percentage points.