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Warning lights are flashing for Democrats as they impeach Trump

(CNN) The House has voted to impeach President Donald Trump for abuse of power and obstruction of Congress -- both tied to his actions around a July 25 call with Ukrainian President Volodymr Zelensky.

But there's growing evidence that the public impeachment proceedings may actually be helping Trump politically.

Take a new Gallup poll released Wednesday morning, before the House vote, which shows two things happening since House Democrats, led by Speaker Nancy Pelosi of California, opened up a formal impeachment inquiry in October regarding Trump's conduct with Zelensky:

1) Trump's job approval rating has gone from 39% to 45%

2) Support for Trump's impeachment and removal has dipped from 52% to 46%.

Those results largely affirm other data out over the past week or so that suggest support for impeachment has dipped. In a CNN national poll released earlier this week, 45% said they supported the impeachment and removal of the President -- down from 50% who said the same in a mid-November CNN survey. That same poll showed opposition to impeachment/removal at 46%, up 4 points from mid-November. And a CNN "poll of polls" -- an average of all six most recent quality/credible national polling conducted between December 4 and December 15 -- showed 46% favored impeachment and removal as compared to 49% who did not.

Now, as I have noted previously, these numbers are not "good" for Trump -- as he so often takes to Twitter to proclaim. Compared to recent past presidents -- including Bill Clinton, who actually was impeached -- a significantly lager chunk of the public now favors Trump's removal than ever felt that way about Clinton, Barack Obama or George W. Bush. In fact, Trump's current numbers on impeachment are most similar to those of Richard Nixon in the spring of 1974. (Articles of impeachment on Nixon were approved by the House Judiciary Committee but never came to a floor vote because Nixon resigned first.)

But what the trend line in recent weeks suggests is that the intense focus on impeachment has marginally helped, not hurt Trump. The change in public opinion is slight, yes. And it may well be temporary. But for the moment, it's the sort of thing that has to make Democrats a little (and maybe more than a little) nervous about the path they have chosen.

Remember this: Pelosi did not want to go down the impeachment path. She stood athwart her party over the summer as more and more of her Democratic members announced their support for an impeachment inquiry over Trump's conduct in connection to special counsel Robert Mueller's investigation into Russian interference in the 2016 election. Her concern, which she voiced publicly and privately, was that a partisan impeachment -- one without significant bipartisan support -- would too bitterly divide the country to make it worth doing.

Here's exactly what Pelosi told The Washington Post magazine on that very topic:

"Impeachment is so divisive to the country that unless there's something so compelling and overwhelming and bipartisan, I don't think we should go down that path, because it divides the country. And he's just not worth it."

That all changed in the fall, when a whistleblower complaint regarding Trump's actions on that July 25 call surfaced. It rapidly became clear that Trump's behavior on the call was a dam-breaker -- Pelosi could no longer stand in the way of the momentum within her caucus to move toward impeaching the President.

But simply because Pelosi acquiesced to that inexorable momentum does not mean that her concerns about the politics of impeachment had changed. What Pelosi knew then -- and knows now -- is that impeachment is a chaos-creator in the American electorate. There is simply no certainty about how the voters -- particularly the small number of independent and/or undecided voters -- will react to all of this.

And the early returns -- emphasis on the word "early" -- have to make Democrats worried.

This story has been updated to reflect Wednesday's House vote to impeach Trump.