"I'm not certain that the Democrats are winning yet in terms of the messaging game. In the presidential Democratic primary, there's a lack of a clear message – obviously anti-Trump, but not much more," said Scot Schraufnagel, a political scientist at Northern Illinois University.
Pelosi's change of heart followed announcements of support for an impeachment inquiry from several more moderate Democratic lawmakers, including a Washington Post column earlier this week by seven first-term House Democrats with military and national security backgrounds, including Spanberger.
U.S. Representative Elissa Slotkin, one of the seven, said she had been urging Democrats to communicate clearly what they are investigating. She did not deny earlier reports she told a closed-door meeting of Democrats on Tuesday that "if you are asking us to stay on message, give us a goddamn message to stay on."
"I am doing everything I can to explain to people how I came to the decision. Because my hope is, even if they disagree with the decision, they give me the benefit of the doubt," Slotkin said.
Absent any other unified message, Dan Kildee, the Democrats’ chief deputy whip in the House, described the Post column as "sort of our manifesto at this point."
Democrats were heartened by what they saw as possible cracks in the usually monolithic Republican ranks of Trump supporters.
On Tuesday, not a single Senate Republican spoke out against a resolution urging the White House to hand over the whistleblower complaint on Ukraine to the intelligence committees in Congress.
Some Democrats said the more straightforward details of the Ukraine call made the issues easier for voters to understand than previous controversies that engulfed Trump, including the lengthy investigation into possible Russian interference and collusion in the 2016 election.
"This is a much easier case to make than some of the Russia stuff," said Jim Manley, a Democratic strategist and former aide to Senators Harry Reid and Edward Kennedy.
But he said Democrats would need a point person to deliver a "clear and coherent message" on the need for impeachment. He suggested one of the House committee chairmen leading investigations such as Adam Schiff, who heads the House Intelligence Committee.
Schiff agreed the Ukraine flap would be easier to explain to voters, saying Trump's conversation with the Ukrainian leader read "like a classic mob shakedown."
