Potential liabilities of Gov. Whitmer, Newsom in Biden replacement scenario

California Governor Gavin Newsom campaigns for President Joe Biden on July 4, 2024 at a county Democratic Party event in South Haven, Michigan. Newsom's appearance in Michigan comes as Biden faces pressure to drop out of the presidential election race. Chris duMond/Shutterstock

While Gavin Newsom has been floated as a potential replacement should President Biden heed the calls of the Democratic Party and drop out of the 2024 presidential race, the liberal governor may not be the strongest candidate to take on former President Trump, a California political observer told Fox News Digital.

Newsom may be popular among Democratic leaders and the progressive caucus for the Golden State's liberal policies, but it's unclear how popular he would be on a national ticket. In his own state, Republicans have railed against the governor's policies on the economy, homelessness and crime.

"Nevertheless, his popularity even here in California is sliding, with one recent poll showing that a majority of voters think the state is headed in the wrong direction," California Policy Center president William Swaim told Fox News Digital. 

Another potential replacement, Michigan Gov. Gretchen Whitmer, may be a top pick to replace him on the ticket, despite denying involvement in a "Draft Gretch" shadow campaign. But her chances against former President Donald Trump in November would be an uphill battle, according to another expert.

Her weakness, according to presidential historian and former Bush administration secretary Tevi Troy, is that Whitmer is not particularly well-known among the average American as someone of prominence.

"She's a popular governor in a swing state," said Troy, who is also a senior fellow at the Bipartisan Policy Center. "So, she's got a lot of positive qualities, but at the same time, she's not truly vetted, and most of these people who could potentially face Trump or replace Biden are not fully vetted."