Is that it? Is that all they’ve got?

Day One of impeachment was not exactly must-see TV. Sure, it was interesting and substantive at times, which would be compliments if this were a graduate school seminar about the lonely lives and confusing experiences of far-flung diplomats.

But this was a congressional hearing to determine whether to file charges against and ultimately remove the president of the United States. By that standard, the Adam Schiff show was a flop.

I would call it a sensational flop, except that would suggest a sense of drama the day never produced. A five-hour slog that doesn’t hit pay dirt or end up anywhere meaningful can’t be sensational.

The Schiff show was more of a quiet, methodical flop. Imagine a slow leak in a big balloon and you’ll get the picture.

Still, the impact is significant. At the start of the day, impeachment was a one-party fever, and so it remains.

Nothing that happened Wednesday changes that critical dynamic. At this point, time and public patience are not the impeachers’ friends.

The lack of surprising or even new developments are major strikes against them. They have the burden of proving their hatred for President Trump is based on something other than resentment over his election or his tweets. That should be a fairly low bar, but they couldn’t get over it.

Although the hearing wasn’t as deadly as special counsel Robert Mueller’s hapless final appearance, it certainly didn’t move the Dems closer to their goal of running Trump out of town.

If Schiff, the zealous California chair of the intelligence panel, has a compelling vision about how to persuade the public that the president committed crimes or anything approaching crimes involving Ukraine, it escapes me. The first day of hearings and the first witnesses should have at least been able to produce facts and tantalizing hints that would leave viewers wanting more.

Instead, the performances of acting Ukraine Ambassador William Taylor and State Department official George Kent left the impression there is little or nothing more to want. Everything to come likely will offer only more detail about the things we already know.

As several GOP members argued, it is impossible to prove the allegations of a quid pro quo when Ukraine got the American aid even though it never promised to investigate that country’s role in the 2016 election or the hiring of Hunter Biden by an energy company for $50,000 a month when his father was vice president.

That idea was captured best when Ohio Republican Jim Jordan got Taylor to acknowledge he had three meetings with Ukrainian President Volodymyr Zelensky over a 55-day period after the Trump phone call. Not once, Jordan said and Taylor agreed, did Zelensky complain that Trump was pressuring him to do the investigation or that there had been a holdup in aid.

“And you’re the star witnesses,” Jordan said, which got a laugh out of Taylor and many in the room.

It was a compelling moment that underscored the difficulty — and maybe the insanity — of what Democrats are trying to do. Moreover, even if they could prove a quid pro quo, would the American people find it impeachable just 11 months before an election? Would the Senate convict and remove Trump on such thin gruel?

Schiff seemed to sense the problems with his case and tried to argue that Zelensky had to fear retribution from Trump. It was a clear suggestion that the Ukrainian president was lying when he repeatedly said publicly he felt no pressure from Trump.

As Republican John Ratcliffe of Texas put it, if Dems believe that, they would have to impeach two presidents — Trump and Zelensky.

Rep. Joaquin Castro (D-Texas) trotted out the most ridiculous argument of the day, saying the fact that the investigations into the Bidens and 2016 didn’t happen doesn’t really matter.

“Is attempted murder a crime?” he asked the witnesses. Perhaps he was joking, but I’m afraid he was serious.

Unfortunately, Schiff is also serious about not wanting to hear the other side of the story. He refuses to summon the so-called whistleblower, and his party shows absolutely no interest in learning why Hunter Biden got rich while his father was visiting Ukraine repeatedly.

Republicans kept bringing up both topics and Kent acknowledged that he had raised concerns nearly four years ago about the “perception of a conflict of interest” with the State Department and Biden’s office, but got no ­response.

Similarly, Dems and their media handmaidens mock Trump’s interest in what role Ukraine played in 2016, deriding it as a wild conspiracy theory.

But in fact, it is well established that Ukraine’s Washington embassy helped spread dirt on Paul Manafort when he was Trump campaign chairman and that some Ukraine officials met with Hillary Clinton aides and other Democrats in 2016. Among them was Alexandra Chalupa, a former Democratic National Committee contractor who worked with Ukrainians to get dirt on Trump.

According to Rep. Devin Nunes, the top Republican at Wednesday’s hearing, Dems took her name out of the testimony transcripts before releasing them. That’s ­curious.

All of which points to the biggest problem with the Schiff show. Dems obviously fear a fair and complete investigation of all the facts, one that reveals their contacts with the whistleblower, his political connections and all the events involving Ukraine and the Bidens.

What are they hiding?