GOP's Portman seeks to make inroads with labor in the race against Strickland.
Party platform calls for replacing oil and gas with renewable energy by 2050.
Trump accuses "Hillary & the Dems" of trying "to rig the debates."
One hundred days from now, either Hillary Clinton or Donald Trump will be elected president.
The vice president says Republicans are violating the Constitution.
"Maybe they're a Hillary person," Trump said.
Clinton increased her lead since last week's poll.
Trump holds a rally in Denver.
Romney said he could also see Trump losing in a landslide to Clinton.
Timothy Cama 07/29/16 07:03 PM EDT
"I think if the voters are voting for it, that’s up to them," Trump said.