The Delaware senator told two Obama aides during the 2008 election that he was too old to make another run for the White House.
"There's something going on at Fox, I'll tell you right now. And I'm not happy with it," Trump told reporters on Sunday.
While former Vice President Joe Biden may be reigning in the polls, the Democratic electorate is far from tethered to their first choice.
A new Fox News poll showed Trump losing to Joe Biden, Kamala Harris, Bernie Sanders and Elizabeth Warren in head-to-head matchups.
More betters are putting their money behind Senator Elizabeth Warren to triumph over former Vice President Joe Biden in the Democratic race.
"President Trump has changed what the electorate is willing to accept when it comes to politics and campaigning, he's changed the standards."
In a New York Times op-ed, the presidential candidate for 2020 said: "We have to get these weapons of war off the streets."
"Don't play games with me, kid," the former vice president told a young conservative who baited him with a question about gender at the Iowa State Fair.
Biden referred to "the tragic events in Houston today and also in Michigan the day before" during a fundraising event.
The Democratic debates last week sounded like a fundraising telethon to support government handouts.
"Warren and Sanders are saying... Barack Obama wasn't that great of a guy after all," Griff Jenkins said.
Senators Kamala Harris and Cory Booker, who took turns railing against Biden, did not appear to have reaped significant gains from their performances.
"We will be ending the AIDS epidemic shortly in America, and curing childhood cancer very shortly," Trump told supporters at a Cincinnati rally.
"[Biden's] defending Obamacare, and being ripped by nine different people for doing it," Brian Kilmeade pointed out.
The former VP made the comment while shaking hands with the California senator ahead of Wednesday's debate in Detroit.
"If you agree with me, go to Joe3-0-3-3-0 and help me in this fight, thank you very much," Biden said during his closing statement.
The message was directed at all candidates but Biden in particular because he has not apologized for deportations that occurred while he served as vice president.
Biden and Harris will face a month after she burned him in the Miami debates over his reminiscence of working with segregationists in the past.
After Joe Biden said reduced costs under Medicare for All were a "fantasy" Bernie Sanders fires back, calling Biden's remarks "disingenuous."
"I would rather him not get engaged," former Vice President Joe Biden told The New York Times.
New York City Mayor Bill de Blasio had the highest unfavorable rating, at 30 percent, of the 10 candidates measured.
Democrats "are enraged by Donald Trump, and it means they're gonna show up," said Cruz about the upcoming election.
The president railed into members of the "Squad' and said BS at his rally Wednesday night in Greenville.
"That sounds suspiciously like Donald Trump," Jess McIntosh warned on CNN.
Nearly every single 2020 Democratic presidential candidate condemned President Trump's "go back" tweet on Sunday.
Senator Kamala Harris of California also polled ahead of the president by one point, at 45 to 44 percent. But that lead falls within the poll's margin of error.
In a new Fox News poll released Thursday, Biden towered above his Democratic challengers at 35 percent in the crucial primary state of South Carolina.