The Associated Press / Democrats, including House Intelligence Committee Chairman Adam Schiff, D-California, are beginning to learn what Flyover Country thinks about the impeachment inquiry hearings he led.

Democrats didn't need to convince any of their supporters that President Donald Trump needed to be impeached. They were all in from the 2016 election on a Russia conspiracy. Or they'd go for the payoff of an alleged sexual assignation. Or enriching the family. Or taxes. Whatever it took.

So when it was suggested a call from the president to the new Ukrainian leader was improper and could be the issue that got them to impeachment, they were sitting on go.

Since then, Trump haters have been doing their dead level best, tweeting snarky messages, posting helpful media stories, debating how awful it all is with like-minded friends.

However, especially within the interior of the country, Democratic voices have been one big echo chamber, one big preaching to the choir spectacular.

Trump supporters, after all, know for whom they voted. They voted for a New York City businessman, for a talk show huckster, for a man born on third base, for a serial philanderer, for a man who makes intemperate remarks, for someone who couldn't utter three verses of Scripture, for a man who isn't a wide reader, for the bull in a china shop. But for a man, they believe, who could get things done, and has.

And they haven't heard every word uttered in the impeachment inquiry hearings or read every piece of evidence House Intelligence Committee members may have.

But they know what they've heard or read doesn't amount to enough to remove the president from office. So he mentioned that the Ukrainian president could look into some potential mess involving former Vice President Joe Biden and his son involving a Ukrainian energy company. So some aid to the country, where corruption is rampant, got held up briefly.

They may even know the aid eventually was delivered and no investigation on the part of the Eastern European country was forthcoming. And that the alleged whistleblower was an Obama administration hire and has prominently been pictured with Washington's most powerful Democrats. But they can't wrap their heads around any action that's been made public that doesn't go on all the time or hasn't been done in other administrations.

That's just a bridge too far.

For those Trump supporters who were around for the Nixon and Clinton impeachment investigations, they see things differently this time around.

Nixon, after all, covered up a burglary that was carried out in his campaign's name, even if he didn't know about it from the outset. He discussed hush money that might be paid. He lied and stonewalled about what he knew until he had no more support in Congress.

Clinton and his wife, Hillary, despite their repeated denials, were involved in numerous scandals before and during his presidency. Even if they had been innocent in three-fourths of the alleged misconduct, it stretched the public's imagination to believe none of them had a scintilla of truth. Finally, Clinton was impeached for perjury and obstruction of justice involving a sexual harassment lawsuit against him. The Senate, nevertheless, acquitted him by failing to achieve a three-fourths majority for conviction.

Trump, on the other hand, released a transcript of his call early in the process, essentially telling the American people, "Read and judge for yourself whether you believe this exchange rose to the level of something truly improper." And testimony from various witnesses has backed him up, though Republicans and Democrats have their own take on what each one said and meant.

(Read more: Impeachment fight leaves voters cold in contested Wisconsin)

Having completed their impeachment investigation, the House Intelligence Committee Democrats now will send a report to the House Judiciary Committee, which will have its own hearings.

Before that happens, though, Democrats are beginning to realize where Middle America stands on the proceedings, though they should have known already. The desire for impeachment, depending on the public opinion poll cited, either hasn't changed or has declined during the hearings. It hasn't gone up. Interest among independents, important for both parties, has definitely declined.

A Michigan Democrat in a district that voted heavily for Hillary Clinton in 2016 has backed away from her desire to impeach the president, seeing no "value" in it. Others in the party are talking a potential censure rather than impeachment. Still others are worried a potential Senate trial would expose Biden, the Democrats' polls leader for the 2020 nomination, and his son, Hunter, to their involvement in Ukrainian politics.

We've said we don't believe House Democrats will be able to help themselves from impeaching Trump. Once they started the ball rolling, it will be difficult to stop it. The majority left fringe of their party demands it.

But now there are cracks in the once-solid impeachment wall. Outside of their echo chamber, few are demanding it. A declared Democratic candidate recently told Times Free Press editorial writers no one brings it up. Without more damaging evidence, a Senate acquittal of an impeached Trump is a near certainty but a likely election boost for him.

Unfortunately for them, Democrats are in a no-win situation. But it's a situation in which they put themselves.