Libertarian presidential nominee Gary Johnson trails the pair by 19.8 points.
Sean Spicer said Clinton shares President Obama's "misguided" economic beliefs.
"I'm a Democrat, and that's worth fighting for," Nina Turner said.
"His movement is moving on," Jill Stein said.
Reid Wilson 07/21/16 01:13 PM EDT
Kansas Secretary of State Kris Kobach is a rising GOP star.
Trump's selection of the Indiana governor for his running mate has set off a mad scramble.
Reid Wilson 07/15/16 01:16 PM EDT
Already, three candidates have formally said they will seek to run for Pence’s job.
Reps. Susan Brooks and Todd Rokita moved quickly after Trump's announcement.
GOP Reps. Susan Brooks and Todd Rokita hope to replace Pence if he's picked for VP.