On March 27, Republican presidential candidates Ted Cruz and Donald Trump exchange jabs over a National Enquirer article alleging extramarital affairs by Cruz and a revealing photo of Trump's wife distributed by an anti-Trump super PAC. (The Washington Post)

Oh, dear.

Most of last week, American voters watched as two of the nation's Republican presidential contenders accused each other of insulting the other's wife and engaging in underhanded and inappropriate campaign tactics. And on Sunday, the accusations continued to fly in both directions.

On various Sunday morning political talk shows, both Donald Trump and Sen. Ted Cruz of Texas spoke about a National Enquirer story claiming that Cruz has engaged in extramarital affairs and about allegations that both men had inappropriately launched or been involved in attacks on the other's spouse.

The Cruz vs. Trump marriage-centered conflict came up on "Fox News Sunday," CNN's "State of the Union," ABC's "This Week," NBC's "Meet The Press" and CBS's "Face the Nation."

Much as he had all of last week, Cruz told the viewers of "Fox News Sunday" that a story that appeared in the National Enquirer last week alleging that he has engaged in multiple affairs is "garbage." Then, he described what he views as the more-than-coincidental personal connection between Trump and David Pecker, chief executive of the company that owns National Enquirer. This is the key portion of what Cruz said:

Look, this story is garbage. It is tabloid smear. And it came from Donald Trump and his henchmen. ...These are complete made-up lies. They're garbage. But, you know, it's indicative of just how low Donald Trump will go. He makes up lies and attacks. ... And I'll note, David Pecker, the CEO of National Enquirer, is a close friend of Donald Trump. The National Enquirer has endorsed Donald Trump for president. And — and this entire campaign they've done two things: One, they've praised Donald Trump at every turn. And, two, they spread lies and smears and attacks on every — every one of his opponents. And — and — and this is garbage. ...

Look, we've got real problems in America. There — there are right now people — people are hurting. Their wages are stagnant. I mean people are out of work. They want to see jobs. And what does Donald Trump want to do? He doesn't want to talk about these issues. He doesn't — he has no answers for how to bring jobs back to America. Donald Trump has no idea how to do that. He has no answers for how to keep America safe from radical Islamic terrorism. So instead, he attacks my wife, he attacks my family. He goes to garbage and sleaze and lies.

It's categorically false, and it has no business in politics. This is why people are disgusted in politics. And — and we need a — a leader who is prepared to address the real challenges facing this country.

On "The Week," Trump again categorically denied any role in the National Enquirer story, describing the publication's work as totally unconnected to his campaign's goals. In a conversation with guest host Jonathan Karl, Trump also said the handiwork of an anti-Trump super PAC that last week financed ads in Utah featuring a nearly nude photo of Trump's wife should be understood as a "disgusting" yet typical Cruz campaign tactic and the origin of the entire fiasco.

KARL: Let's go back to the thing that started this all off. You mentioned, of course, in fairness, you did not start this. This started with that super PAC ad featuring Melania. But in response...

TRUMP: And he's very close to the super PAC, just so you understand. And there's no way in a million years that super PAC did that without his absolute knowledge.

Don't forget, I call him Lying Ted. I call him that because nobody that I've known — I've known a lot tougher people over the years in business — but I've never known anybody that lied like Ted Cruz.

KARL: But let me ask you, though, because in response you said in that tweet that you would spill the beans on Heidi Cruz. What did you mean by that? Spill what beans?

TRUMP: Well, there are things about Heidi that I don't want to talk about, but I'm not going to talk about them.

I mean, you know, you can look. But I wouldn't talk about them.

KARL: What really set Cruz off was when you retweeted that photo, that unflattering photo of Heidi Cruz.

TRUMP: Well, it was a retweet that somebody sent to me. And it was a retweet.

Now, look, what he did was far worse. I mean, he takes out a thing and sends it to Utah to the voters of Utah and it was a cover shoot and it was, you know, by a big magazine. She was a very, very successful model, big model, and did lots of shoots and lots of cover shoots. And to send that like it was some kind of bad picture was disgusting to me. I thought it was disgusting.

And they put the, you know, they make me like the bad guy here. I'm just responding to what he does. I respond. I counterpunch, but I'm responding to what he does.

But always the press likes to make me the bad guy. He's the one that started it. He knew about the picture. He may have even bought the rights to the picture, meaning his campaign. And the super PAC had it. He's very close to the super PAC. I didn't start this. He did.

Legally, campaigns cannot directly coordinate their efforts with outside super PACs, nonprofit organizations that do not have to disclose their donors. Cruz has denied involvement in the ads featuring images of Trump's wife. The ads were financed by a super PAC known as Make America Awesome.

But over the course of the presidential campaign, several other candidates have demonstrated a willingness to test this boundary, The Washington Post's Matea Gold reported in July.