The final weeks of a midterm campaign is when everyone, from political operatives to media outlets, drops their worst oppo.

That’s when voters are paying the most attention and when a competitive race can break a certain way. That’s especially true with this fall's Senate races, where a single battleground state may determine whether Mitch McConnell becomes majority leader again.

The contest in Georgia just got rocked by a new round of accusations against Herschel Walker, which he denies.

The former football star, challenging Democratic Sen. Raphael Warnock, has already survived a negative onslaught that would sink almost any other candidate. These range from an ex-wife charging threats and abuse to the emergence of previously unannounced children by a man who’s crusaded for black fathers to do their duty. He’s tried to lighten this baggage by admitting to past mistakes and mental health problems, and at times has been in a statistical tie with Warnock.

Now comes an allegation that is very difficult to explain away.

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Walker is 100% pro-life and would ban abortion in his state, likening it to murder, with no exceptions.

So charges of hypocrisy took center stage when the Daily Beast reported an accusation by an ex-girlfriend that Walker paid for her abortion in 2009. He denies, this, calling it a "flat-out lie."

Here’s the evidence involving the woman, who was not named: "She supported these claims with a $575 receipt from the abortion clinic, a ‘get well’ card from Walker, and a bank deposit receipt that included an image of a signed $700 personal check from Walker.

"The woman said there was a $125 difference because she ‘ball-parked’ the cost of an abortion after Googling the procedure and added on expenses such as travel and recovery costs.

"Additionally, The Daily Beast independently corroborated details of the woman’s claims with a close friend she told at the time and who, according to the woman and the friend, took care of her in the days after the procedure.

"The woman said Walker, who was not married at the time, told her it would be more convenient to terminate the pregnancy, saying it was ‘not the right time’ for him to have a child."

Asked about the check by Fox News' Sean Hannity, Walker said: "I send money to a lot of people. I believe in being generous."

Sorry, but that’s a really weak response. What are the odds that a woman that Walker chose to be generous with just happens to be the one saying he paid for her abortion, and has a receipt from the clinic?

And there is a one-two punch here, with Walker’s 23-year-old son Christian, who has defended his father and campaigned with him, suddenly turning on him.

"You’re not a ‘family man’ when you left us to bang a bunch of women, threatened to kill us, and had us move over 6 times in 6 months running from your violence," he tweeted.

Herschel Walker responded: "I LOVE my son no matter what."

That brought even stronger language from Christian, with a tweet he later deleted: "You have 4 kids that we know of and you weren’t in the house raising ONE of them, you were out cheating and lying. If you loved your kids you’d be raising them instead of running for a senate race to boost your ego." 

What’s more, Christian said family members had discouraged his dad from running for the Senate "because we all knew (some of) his past."

There is something about a son turning on a father that feels more dramatic and persuasive than allegations from an ex-wife, which might be written off as the product of a bitter divorce.

Christian’s mother, Cindy Grossman, has spoken of the time that Herschel "held the gun to my temple and said he was going to blow my brains out." Grossman, who was married to him for two decades, has made an ad with such graphic allegations.

Football legend or not, Walker’s going to have a hard time outrunning the abortion allegation.

In the Senate race in another battleground state, Pennsylvania, Dr. Oz trails Democrat and stroke victim John Fetterman by a half-dozen points in most polls. Oz is now being hit with one allegation I view as totally fair game and another that decidedly is not.

WHEN A MAJOR HURRICANE COLLIDES WITH OTHER NEWS, THE STORM PREVAILS

The Washington Post leads off its piece this way:

"Mehmet Oz looked directly into the camera and introduced his daytime television viewers to a ‘controversial’ weight loss approach: taking a hormone that women produce during pregnancy combined with a diet of 500 calories a day.

"‘Does it really work? Is it safe? Is it a miracle? Or is it hype?’ he asked in a 2011 episode of ‘The Dr. Oz Show’ before introducing his audience to ‘human chorionic gonadotropin,’ or HCG, and to a weight loss doctor who promoted it.

"In fact, there was little uncertain about the HCG Diet. Numerous studies conducted years before Oz’s show had shown that the fertility drug does not cause weight loss, redistribute fat or suppress hunger. Ten months later, the Food and Drug Administration warned seven companies marketing HCG products they were violating the law by making such claims, and the agency issued additional warnings to consumers in subsequent years. Nevertheless, Oz revisited the topic in 2012, providing a platform for the same weight loss doctor, who claimed that HCG worked."

There are other examples, and the reason this is legitimate is that Oz’s controversial promotions were debated for years when he was just a television celebrity. And that role, of course, formed the basis of his candidacy, that he was a successful entrepreneur who could be trusted.

An Oz spokesman said the show was designed to present all kinds of views, and it’s "idiotic and preposterous to imply" that the doctor shared those beliefs.

Which brings us to yesterday, when NBC used its website to promote anti-Oz piece that is, quite simply, outrageous:

"From 1989 to 2010, research by Dr. Mehmet Oz — the television personality and Republican Senate candidate in Pennsylvania — inflicted suffering on and killed over 300 dogs, 31 pigs and 661 rabbits and rodents. It was during Oz’s time as a principal investigator at a Columbia University lab." The report was attributed to the website Jezebel.

This is a ridiculous cheap shot, written by a professor with an obvious agenda, that implies Oz was some ghoulish dog-killer. The truth is that all doctors, scientists and researchers rely on animal testing when it comes to new drugs. Actually, it’s even worse: They are required by law to perform animal testing.

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Oz is no different than all of his colleagues in the field.

Now the deaths of these animals is of course regrettable, but the alternative – testing potentially harmful drugs on humans – is unthinkable.

The activist professor, Brian Kateman, heads a foundation dedicated to reducing consumption of animal products. He sees irony in the Senate last week passing a new FDA law – updated from 1938 – that would eliminate the animal testing requirement. That’s a separate debate. But you can’t turn around and demonize a doctor who was following a decades-old law just like everyone else in his field.

This is just the beginning of the hit pieces and oppo research dumps – and we’ll see whether they’re mainly aimed at one political party.