After weeks of dancing around its constitutional authorization to impeach a president suspected of warranting it, the House of Representatives appears on the verge of initiating the formal process.

House Judiciary Committee Chairman Jerrold Nadler of New York has rebuked the Justice Department’s call for negotiations, suggesting he’s ready to issue his threatened subpoena to retired Special Counsel Robert Mueller to testify.

Mr. Mueller has insisted that even if he honors the subpoena by showing up, he has no intention of going beyond his written report. But saying so and actually clamming up before interrogating and insisting congressional members may be another matter.

As House Speaker Nancy Pelosi opts to do more intimidating fact-finding before pulling the trigger, more and more House Democrats are calling for the impeachment process to begin now. House Majority Leader Steny Hoyer of Maryland, while backing his speaker, has made clear he has heard them.

Among those arguing that the Democrats can’t wait any longer to counter President Donald Trump’s assault on the nation’s political norms are two declared presidential candidates, Sen. Elizabeth Warren of Massachusetts and Mayor Pete Buttigieg of South Bend, Ind.

Both have begun to demonstrate in public opinion polls some positive separation from the pack of 23 Democratic hopefuls vying to take on Mr. Trump next year. Two Democratic debates in which 10 of them at a time will square off will occur next month.

Former Vice President Joe Biden is leading the flock in the polls with 35% or more of the vote, with Vermont Sen. Bernie Sanders second but slipping slightly, as many of the other candidates challenge him for the mantle of the party’s most progressive entry.

But Mr. Biden openly contends that his 44-year record — 36 years in the U.S. Senate and eight as veep — gives him credentials in both the progressive and liberal-to-moderate camps. Ms. Warren and others of the party’s left have begun to remind voters of Mr. Biden’s verbal gaffes and actual policy stances in hope of narrowing his large early lead.

But with so many Democrats going after the party nomination, Mr. Biden is far from achieving a majority. Many more Democratic debates plus the competition for national convention delegates in all the state primaries and caucuses lie ahead beginning next January.

Once again, the process will begin with the Iowa caucuses and the New Hampshire primary, and the so-called Super Tuesday on which multiple voting events processes will occur earlier than ever, in the first week of March 2020.

Last weekend, 14 Democratic hopefuls, including Ms. Warren, Mr. Buttigieg and home state favorite Sen. Kamala Harris, gathered in San Francisco vying for support, amid talk of the absence of Mr. Biden, who chose instead an event sponsored in New Jersey by a same-sex oriented political group.

Mr. Biden already is being singled out by other contenders for controversial positions in the past. They notably include his support of a crime and incarceration law aggressively opposed in the African-American community, for his opposition to cross-city school busing Delaware, and for his chairing of the Senate Judiciary Committee confirmation hearings of Clarence Thomas, who was narrowly placed on the Supreme Court in 1991.

Specifically, Mr. Biden has been criticized for failing to call a black woman, Angela Wright, to testify in Mr. Thomas’ confirmation hearings. She is said to have had damning testimony against Mr. Thomas. Another accuser, Professor Anita Hill, did testify at length, and Mr. Biden has said he regrets not having been able to get Ms. Wright to do so when she declined at the eleventh hour, for reasons of her own.

These, along with old allegations of plagiarism against Mr. Biden for cribbing lines from a speech by a prominent British politician, have been rehashed often, with little noticeable effect on his lead in the polls.

Attempts to cast Mr. Biden as hiding from the public and Democratic competitors may run out of gas, however, since he is expected to be in the approaching DNC debates that will be open to all areas of discussion. Those on the same stage with him will have a chance to cut him down to size. So it is up to the former vice president to take the case for himself whether his time is past in a party said to be drifting ever leftward.

Jules Witcover is a syndicated columnist and former long-time writer for The Baltimore Sun. His latest book is “The American Vice Presidency: From Irrelevance to Power” (Smithsonian Books). His email is juleswitcover@comcast.net.