MILWAUKEE — Senate Majority Leader Chuck Schumer “forcefully” shared with President Biden concerns about him leading the 2024 Democratic ticket and encouraged him to step aside, according to a new report.

“Schumer forcefully made the case that it would be better for Biden, better for the Democratic Party, and better for the country if he were to bow out,” ABC News’ Jonathan Karl said on air Wednesday while reporting live from the Republican National Convention in Milwaukee.

The Democratic National Committee confirmed Wednesday morning it was delaying plans to virtually nominate Biden for a second term — after Schumer privately asked fellow party leaders for more time to deliberate.

A source close to both Biden, 81, and Schumer, who met in-person on Saturday at Biden’s Delaware vacation home, told The Post that the men specifically discussed bleak polling numbers.

House and Senate Democrats are expressing alarm internally that Biden could lose in a landslide to former President Donald Trump, 78, and drag down other members of his party, possibly causing a Republican sweep of key congressional races.

“Down-ballot Dems can only run so far behind a nominee who is losing in every swing state,” a congressional source told The Post this week.

A Schumer spokesman confirmed to The Post that the New York Democrat “conveyed the views of his caucus directly” to Biden — but dismissed Karl’s reporting.

“Unless ABC’s source is Senator Chuck Schumer or President Joe Biden the reporting is idle speculation,” the spokesman said.

Schumer trekked to Biden’s vacation home in Rehoboth Beach, Del., to make his views clear over the weekend after more than 20 congressional Democrats had called on the president to abandon his re-election effort.

Biden told Schumer and House Minority Leader Hakeem Jeffries (D-NY), who also recently spoke with the president, that he’s not going anywhere, the White House said Wednesday night.

“The President told both leaders he is the nominee of the party, he plans to win, and looks forward to working with both of them to pass his 100 days agenda to help working families,” a White House spokesman said.

Calls for Biden to relinquish the nomination have mounted since the president’s catastrophic debate performance against Trump, 78, on June 27 and his bungled “big boy” press conference at the NATO summit in Washington, DC

Media interviews in the weeks since the debate flop have showcased incoherent remarks, delivered in the same tired and raspy voice that marked his other public appearances.

One “rambling” private phone call recently held with Democratic lawmakers was reportedly even worse than the debate.

“He’d start an answer then lose his train of thought, then would just say ‘whatever.’ He really couldn’t complete an answer. I lost a ton of respect for him,” one person on the call told Puck News.

“The president was rambling, dismissive of concerns, unable or unprepared to present a campaign strategy,” another told the outlet.

While his aides have ignored demands that he undergo medical testing, the president stressed to ABC News’ George Stephanopoulos that he has “a full neurological test every day.”

In a BET interview released Wednesday, Biden changed his tune and said he would reconsider his candidacy “if I had some medical condition that emerged, if somebody, if doctors came to me and said, you got this problem and that problem.”

California Rep. Adam Schiff the same day became the 21st Democrat — and one of the most senior-ranking — to call for Biden to step aside, citing “serious concerns” about his electability.

Schiff had vented that the 2024 race “should not be even close” because the Democratic party leader was “running against a criminal.”

“There’s only one reason it is close, and that’s the president’s age,” he admitted, without directly calling for a new nominee.

Schiff is also a close ally of House Speaker Nancy Pelosi (D-Calif.), who did not inspire confidence last week when she speculated that Biden had still not made up his mind about running — despite many statements to the contrary by the president and his campaign.

“We’re all encouraging him to make that decision because time is running short,” Pelosi said in an interview on MSNBC after having urged others to question whether Biden’s debate flop was “an episode” or “a condition.”

Public polling shows that a majority of Democrats would prefer Biden withdraw, with an AP-NORC survey released Wednesday putting that number as high as 65%. 

It’s unclear whether Biden would favor Vice President Kamala Harris to succeed him if he suspends his campaign, but CNN reported Wednesday that “private conversations” between the White House and Capitol Hill were showing that he was more “receptive” to a replacement candidate. 

“He’s gone from saying, ‘Kamala can’t win,’ to ‘Do you think Kamala can win?” a senior Democratic adviser told the outlet.