House Democrats have officially begun impeachment proceedings, a key Democrat confirmed earlier this month.

And the first national poll out since then suggests that House Democrats are going to have to persuade Americans why this step and, possibly, the next steps are necessary.

Monmouth University found that a majority of Americans think it’s a bad idea for the House Judiciary Committee, which takes the lead on such matters, to conduct an inquiry that may lead to Trump’s impeachment.

That’s not to say that Trump is a popular president. His approval rating is at 40 percent in this Monmouth poll, among the lowest readings over the past year. But there is a notable number of people who don’t like him and still think that moving ahead with an impeachment inquiry is a bad idea — 22 percent. That’s not nothing.

Monmouth also did something interesting in this poll: They asked people to share why they thought an impeachment inquiry was a good or bad idea, letting respondents give their own reasons.

Among those who approved of the impeachment inquiry, respondents said Trump deserves to be impeached because he’s a bad president or person at about the same rate as respondents who said he deserves to be impeached because he has done something such as breaking the law. But if House Democrats decide to vote on impeaching Trump, it will be over alleged crimes. (Impeachment is an inherently political process instead of a judicial one, but Congress doesn’t impeach presidents just because they don’t like them.)

Let’s pause here to explain how an impeachment process works. An impeachment inquiry is the first step in the process. Members of the Judiciary Committee are investigating which, if any, articles of impeachment they might write up and have the House vote on. Congress can decide what meets the bar of “high crimes and misdemeanors” that the Constitution spells out for impeachment.

Here, public opinion and House Democrats may be more on the same page. A majority of Democratic lawmakers support an impeachment inquiry, but it’s not clear whether a majority supports impeachment. Since former special counsel Robert S. Mueller III testified to Congress last month, 35 House Democrats have come out in favor of an inquiry. But of those 35, a sizable number — eight — also cited the need to collect evidence, facts or “truth” on Trump. Some have even made clear that while they support an inquiry, right now they wouldn’t vote for an impeachment.

“While I am not ready to support articles of impeachment,” said Rep. Emanuel Cleaver II (D-Mo.) in a July statement, “I am ready to use the full force of Congress to carry out subpoenas that have stalled in the courts. That means the opening of an impeachment inquiry.”

In other words, a majority of House Democrats and a majority of Democratic voters (72 percent) support moving forward with an impeachment inquiry, but once you dig a little deeper you can see that many of them are somewhat hesitant to move forward.

Among those who think an impeachment inquiry is a bad idea, the reasons are below. It looks as if most people who think the inquiry is a bad idea generally support Trump, which isn’t surprising.

But what about those who are less partisan and don’t want to see an impeachment inquiry? Monmouth gets at that, too, by breaking apart the answers of people who disapprove of Trump and think an impeachment inquiry is a bad idea right now. Here’s why they think that:

Why impeachment inquiry is a bad idea -- Among people who also disapprove of Trump

Concern over political retribution for pursuing impeachment is the top reason House Democratic leaders have been hesitant to embrace the inquiry. And based on what we know from this poll, it is difficult to see how impeachment would play out politically. The conventional wisdom, as most prominently espoused by impeachment-reluctant House speaker Nancy Pelosi (D-Calif.), is that seriously pursuing impeachment of Trump will backfire politically and cost Democrats seats in suburban, Republican-leaning districts that helped them win the House majority in 2018.

That might be true, but this poll doesn’t show overwhelming evidence one way or the other. Monmouth found that impeachment could turn off independents slightly more than it engages them for Democrats. Of independents, 25 percent say they would be less likely to vote for their House lawmaker if they support impeachment, while 21 percent say they would be more likely.

Bottom line: It’s not clear what an impeachment inquiry will look like when the House returns from its break next month. But it does seem that Democrats will have their work cut out for them to simultaneously build their case against Trump and persuade Americans this is the right course.

JM Rieger contributed to this report.