Hillary Clinton now holds a 15-point lead over Donald Trump in a new McClatchy-Marist poll.
Here are the latest results, which were released on Thursday:
Clinton: 48 percent.
Trump: 33 percent.
Here's how the presidential contenders fared last month:
Clinton: 42 percent.
Trump: 39 percent.
In a four-way race, here are the results:
Clinton: 45 percent.
Trump: 31 percent.
Libertarian Party candidate Gary Johnson: 10 percent.
Green Party candidate Jill Stein: 6 percent.
"This is coming off the Democratic convention, where a bounce is expected" for Clinton, said Lee Miringoff, director of the Marist Institute for Public Opinion in New York, which conducted the national survey.
"What you don't want is to have the worst week of your campaign," Miringoff said, referring to Trump's dust-up with the parents of a Muslim Army captain who died in Iraq in 2004.