The mainstream media initially locked onto former Vice President Joe Biden's campaign because he was seen as the next establishment candidate, but have since changed their tune, according to Tammy Bruce.

The media are more opportunistic than they are loyal, even to a candidate like Biden, who has been around Washington for decades, Bruce claimed Tuesday on "Tucker Carlson Tonight."

"At the beginning, everyone thought it's just back to the normal rhythm of 'the next in line' and he was going to be president, and they're all over you," she said.

"The moment there is a little bit of a stumble, or a few gaffes, it's like maybe he's not the one -- and it's a free-for-all."

BIDEN AIDE SAYS GAFFES ARE 'PART OF HIS CHARM'

Bruce, president of the Independent Women's Voice and a Fox Nation host, said the perception of Biden was the "problem" the entire D.C. establishment has faced.

"It's not loyalty, it's not even really about Joe Biden," she said.

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"They are now part of the chaos that is ruling the Democratic Party -- nobody knows what's going to happen and the old rules are beginning not to apply."

For its part, the Biden campaign -- through deputy campaign manager Kate Bedingfield -- defended him on Tuesday amid controversy over some recent gaffes.

Biden last week asked a crowd to "imagine" the assassination of former President Barack Obama while recalling the deaths of political heroes Robert Kennedy and Martin Luther King Jr. He also made numerous mistakes while promoting his health care plan, and said he enjoyed being back in Vermont while campaigning in New Hampshire.

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“So, I know it’s just a mistake, but it’s Vermont and New Hampshire, he’s running in the New Hampshire primary. Does he have to be more careful to prove that he hasn’t lost his fastball?” MSNBC anchor Andrea Mitchell asked.

“I think the press has to be more careful about applying an unfair standard to Joe Biden than they’re applying to other candidates,” Bedingfield responded. “If you listen to what the candidates say all day as they’re out campaigning, they’re out in front of cameras, they’re in front of people, they’re talking all day. Everybody’s going to slip up and misstate a name or a date or a location. It happens all the time.”

Fox News' Joseph Wulfsohn contributed to this report.