A previous senior adviser to former President Barack Obama is warning Democrats about a potential threat to President Biden's re-election campaign from third-party candidates like Cornel West, a 2024 Green Party presidential candidate.

David Axelrod, who served as a top adviser to Obama for two years in the White House before becoming the senior strategist for Obama's successful 2012 re-election campaign, is questioning "why alarm bells aren’t going off" for Democrats amid mounting concern over West's candidacy in the race.

Ever since he announced last month he would make a run for the White House as a third-party candidate, West, a progressive activist and philosopher, has largely been dismissed by Democrats as a serious candidate as they work to shore up support for Biden ahead of the 2024 election.

Axelrod, however, insists Democrats should be taking challenges like West's to the incumbent president seriously.

PROGRESSIVE ACTIVIST CORNEL WEST ANNOUNCES PRESIDENTIAL RUN UNDER THIRD PARTY

Cornel West, David Axelrod, Joe Biden

From left to right: Green Party 2024 presidential candidate Cornel West, former Obama senior adviser David Axelrod and President Biden. (Joshua Lott/AFP; Tayfun Coskun/Anadolu Agency; Anna Moneymaker via Getty Images)

"This is going to sneak up on people," Axelrod, a CNN political commentator, said this week. "I don’t know why alarm bells aren’t going off now, and they should be at a steady drumbeat from now until the election."

Similar to Axelrod, Pennsylvania Democratic Lt. Gov. Austin Davis said his party "should be concerned" about the implications of West's candidacy.

"We should be concerned. I don’t think time’s necessarily on our side. The longer these things hang out there, the worse it tends to get," said Davis, according to CNN. "We should try to deal with it rather quickly if we can."

CORNEL WEST CALLS OUT BIDEN'S PAST 'CONNECTIONS' TO SEGREGATIONISTS, SAYS TRUMP ALSO FLAWED ON RACIAL ISSUES

Davis also noted that conversations about West, thus far, have been among insiders rather than voters, the outlet reported.

The mounting concerns from within the party come amid West's targeting of Biden on numerous issues in recent weeks.

Earlier this month, West told Fox News his third-party bid is as "serious as a heart attack" and doubled down on comments he made drawing into question Biden's compassion for the Black community.

Cornel West, Bernie Sanders

Democratic presidential candidate Sen. Bernie Sanders, I-Vt., and political activist Cornel West walk onstage together during a campaign event at the Whittemore Center Arena Feb. 10, 2020, in Durham, N.H. (Joe Raedle/Getty Images)

Criticizing Biden's past relationships with segregationist Democratic senators, West mentioned Biden's praise for former Mississippi Sen. John Stennis, namesake of the NASA Space Center near Kiln, Mississippi. In 2008, Biden reportedly called his fellow Democrat "a hell of a guy."

More recently, Biden regaled supporters at a 2019 fundraiser of his time working with Stennis' fellow Mississippian James Eastland and then-Sen. Herman Talmadge, D-Ga., who supported segregation.

"I was in a caucus with James O. Eastland. He never called me ‘boy.' He always called me ‘son’," Biden quipped of the senator who once warned against "mongrelization." 

Biden was rebuked at the time by fellow Democrat Sen. Cory Booker of New Jersey, who said in a statement obtained by the Daily Mail, "You don't joke about calling Black men ‘boys.'"

On "Hannity," West confirmed he is accusing Biden of "crimes against humanity" against African Americans, as reported by the New York Post.

When Hannity asked West about minority voters continuing to largely support the Democratic Party, which West said is as broken as the GOP, the professor responded that both former President Donald Trump and Biden are flawed on racial issues and both parties are tied to "big money" and corruption.

President Biden delivers an address on 'BIdenomics' in Philadelphia

President Biden speaks at the Philly Shipyard July 20, 2023, in Philadelphia. (Spencer Platt/Getty Images)

"This is true for Republicans, is true for Democrats. [I'm] talking about Brother Trump himself. And Biden's connection to Stennis. Biden's connection to [ex-South Carolina Democrat-turned-Republican Sen.] Strom Thurmond. We know Brother Trump's own father's been tied to the Klan and of Trump's language about Black people," said West.

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During the same interview, West criticized the handling of the White House cocaine incident, which Hannity noted was closed quickly. West agreed that a West administration would not see the same purported deferential treatment in the form of such an accelerated conclusion if drugs were found there.

"For my White House — and I've told my people, I'm not even going to the White House until every American citizen has a house — I want to abolish poverty, abolish homelessness. I want jobs with a living wage," he said at the time.

Fox News' Charles Creitz contributed to this report.