WASHINGTON - Michael Cohen's testimony is just the beginning.

The House oversight hearing with President Donald Trump's former attorney, coming in advance of special counsel Robert Mueller's report, heralds what Democrats in Congress view as the long days ahead providing checks and balances on the Oval Office.

Analysis: Cohen Hearing Stokes Touchy Topic of Impeachment

For some, the outcome may - or may not - lead to grounds for impeachment. For others, impeachment cannot come fast enough.

Analysis: Cohen Hearing Stokes Touchy Topic of Impeachment

What is certain, though, is the mounting tension. As the hearings and investigations unfold, Democrats, particularly those running for the White House, may be speeding toward a moment when they have no choice but to consider the I-word.

Analysis: Cohen Hearing Stokes Touchy Topic of Impeachment

Newly elected Democratic Rep. Rashida Tlaib, among the most outspoken lawmakers on impeachment, says that as the 2020 presidential candidates visit her Detroit-area district, “most residents are going to ask where they stand on this issue.”

Voters are less concerned with Mueller's Russia investigation, Tlaib said, than with the day-to-day White House operations and “whether or not there's a crooked CEO in the Oval Office.”

Hours into Cohen's testimony Wednesday, New Hampshire's statehouse Speaker Steve Shurtleff, a Democrat, said that impeaching the president was becoming a realistic option.

“They're putting a lot of meat on the bone,” Shurtleff said in an interview. “It could be a one-two punch,” he said of the Cohen hearing and Mueller report. “I think it'll connect a lot of dots.”

Trump allies have tried to use the prospect of impeachment as a political weapon. The president's former chief counselor, Steve Bannon, had warned before the 2018 elections that Democrats would impeach the president if they won control of Congress.

Republicans are taking up that mantle. At the start of the Cohen hearing, the top Republican on the panel, Rep. Jim Jordan of Ohio, said the only reason for the session was so Democrats could pursue impeachment. Another committee Republican, Rep. Chip Roy of Texas, called the hearing a “circus” not worth Americans' time. And newly elected Republican Rep. Carol Miller of West Virginia said the sole purpose was “discrediting the president.”

“If it was not already obvious,” Miller said, “there are members here with a singular goal in Congress to impeach President Trump.”

House Speaker Nancy Pelosi has kept calls for impeachment at bay by insisting that Mueller first must be allowed to finish his work, which reports suggest could happen in the coming weeks, and present his findings publicly - though it's unclear whether the White House will allow its full release.

Pelosi says the House shouldn't pursue impeachment for political reasons, nor should it hold back for political reasons. Instead, she says lawmakers need to do their jobs as a co-equal branch of government and go wherever the facts lead.

“The American people expect us to hold the administration accountable,” said Rep. David Cicilline, D-R.I, a member of House leadership. “And if during the course of that we come upon sufficient evidence that warrants his removal, I think they expect us to do that.”

But Democrats are not there yet, at all.

So far, the Democratic Party's potential 2020 class has tried to avoid the impeachment question altogether, fearful that calling for impeachment before the Mueller report is out could undermine the process and trigger a voter backlash.

Among them, only former Texas Rep. Beto O'Rourke has directly called for Trump's impeachment. Others approached the Cohen hearing in more cautious and creative ways.

Sen. Kamala Harris of California, used the hearings as a fundraising opportunity. “Are you watching Michael Cohen testify before Congress today?” campaign manager Juan Rodriguez wrote. “There's a lot to unpack, but it's abundantly clear: if we are finally going to get to the truth, Congress must act to protect Robert Mueller from being fired before his findings in the Russia investigation are made public.” He asked for donations of between $10 and $250.

Sen. Elizabeth Warren of Massachusetts sent an email during the hearing promising, if she becomes president, not to pardon anyone implicated in the Trump investigations. She set down a challenge for others running to do same.

Sen. Amy Klobuchar of Minnesota tweeted that Cohen's testimony “is a big deal.” Sen. Cory Booker of New Jersey said in a brief chat that he wasn't watching the hearing but was “looking to digest it.'

And Howard Schultz, the former Starbucks CEO considering an independent bid, said the testimony is “another stark reminder of President Trump's utter disregard for honesty and decency.”