AMNA NAWAZ: Ohio's senior U.S.

senator is calling for an Ohio congressman who is also his former son-in-law to drop his reelection bid and resign from office.

In a social media post yesterday, Republican Senator Bernie Moreno called Republican Representative Max Miller -- quote -- "a danger to my daughter," writing -- quote -- "I hold my breath every minute he has custody of my granddaughter.

If there are any basic standards of character required to hold elected office, Max Miller fails them."

Moreno had been publicly silent over the past couple of years as allegations and messy divorce proceedings swirled around Miller and Moreno's daughter, Emily.

Senator Moreno's comments followed a live video from Miller over the weekend addressing accusations from his former wife that he abused her and their child.

REP.

MAX MILLER (R-OH): No criminal charge has ever been filed against me.

My former wife is engaging in a pattern of reporting incredible, serious, and destructive allegations with absolutely no evidence.

AMNA NAWAZ: Our congressional correspondent, Lisa Desjardins, joins us now with more.

So, Lisa, let's start with the accusations being made against Max Miller.

What do we know?

LISA DESJARDINS: Some of these accusations go back years.

Some are from this year.

And I should note, this is not the first time a woman has accused Max Miller of domestic abuse and he has denied it.

In this case, it is his ex-wife, Emily Moreno.

She has not spoken publicly, but court documents and photos published by The Daily Mail detail some very serious abuse allegations.

She says that he in different times pushed her, pushed her against her wall, bruised her, held a gun to her head, and at one point doused her with hot water from a sink.

Now, Congressman Miller denies all of that adamantly.

He says the sink incident was horseplay, and the rest of them he says were invented.

There's also an incident with their young 2-year-old daughter in which her collarbone was broken while she was in his custody.

Emily Moreno did not accuse him of that abuse, but did raise concerns.

To that, Mr.

Miller put out documents over the weekend showing the findings of a local investigation which declared that this was an unsubstantiated allegation.

He says the daughter was in a nanny's care at the time of that injury.

This document is one of dozens that Max Miller has put out in his defense.

AMNA NAWAZ: And why is all of this spilling out into the public now?

Why is Senator Moreno weighing in on this now?

LISA DESJARDINS: Right.

This does go back months, but after that collarbone incident, Emily Moreno filed to change their shared custody agreement.

Then, shortly after, Miller won his May primary.

Then The Daily Mail our article came out about these abuse allegations.

Following that, we now had Senator Moreno not weighing in.

Why is he changing now?

Well, speaking to someone who's involved, he says over the weekend they realized that Congressman Miller was ramping up his attacks on his daughter, Emily Moreno, and that as a father he had to weigh in.

Until that point, they say Emily Moreno had asked him not to.

Now he felt he had to spoke -- to speak up.

AMNA NAWAZ: So these custody proceedings are playing out in the courts.

But what do domestic violence advocates say about all of this?

LISA DESJARDINS: This is a high-conflict divorce.

This is complicated in almost every case, even when there aren't members of Congress involved.

But a particular facet here is Congressman Miller's defense.

He is trying to point the finger back at his ex-wife.

He has raised things that says she offered to make him food at the time of these abuse allegations, and she said he was kind.

On one hand, he says that shows she was different in private than her public accusations imply.

But domestic abuse experts say it's not that simple.

We spoke to Joan Meier of the National Family Violence Law Center at George Washington University.

JOAN MEIER, National Family Violence Law Center, George Washington University: Those are the kinds of claims that are very commonly made by alleged abusers.

And they can get traction because they seem counterintuitive.

Why would someone who's been violently assaulted be being nice to their violent assaulter?

The problem is, is that takes it out of context.

LISA DESJARDINS: Separately, we spoke to the National Domestic Violence Hotline.

They said this is still a major issue in the country.

They get 3,000 calls for help a day.

AMNA NAWAZ: Obviously, there's serious allegations here.

As you point out, there's a child at the heart of all of this, but there are political implications given the people here.

What should we know about that?

LISA DESJARDINS: Congressman Miller's in a vulnerable Republican seat, and now Democrats think it may be even more vulnerable.

But it also comes in a year with patterns of these kinds of stories.

For example, Graham Platner in Maine, as we all remember, had to pull out of that Senate race after past allegations of abuse.

You see three congressmen there.

Two of them resigned after sexual misconduct allegations, and then in the middle one, Cory Mills, who still faces those kinds of allegations.

There are now calls for an Ethics investigation into Congressman Miller.

He says he is not resigning, but those Ethics investigations, we know, take time.