(CNN) In a Friday interview with Bloomberg, Speaker Nancy Pelosi perfectly diagnosed the biggest danger for Democrats posed by the ongoing impeachment inquiry.

"There is -- I should say -- a mountain of concerns to be brought up," Pelosi said. But she went on to add that there is a danger of overwhelming the public with charges and details.

"When does the law of diminished returns set in?" Pelosi, of California, asked rhetorically.

That second part of Pelosi's quote is absolutely key when it comes to understanding how much political peril lurks in the ongoing impeachment investigation for Democrats. Put simply, that risk is this: The longer the inquiry goes on and the more strands, people and charges are brought into the conversation, the harder it is for people to follow and understand. And the less people understand about the process -- and why Democrats believe it to be necessary -- the better for President Donald Trump.

Consider this: For months and months, polling showed that a majority of the public opposed impeaching Trump even while, in those very same polls, Trump's job approval rating hovered at or near 40%. People didn't think Trump was doing a good job and didn't want him removed from office.

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