Last week, President Trump baselessly accused former president Barack Obama and former vice president Joe Biden of engaging in corrupt activities.

On Monday, Trump’s own attorney general, William P. Barr, punched a hole in that conspiracy theory — whether he intended to or not.

During a news conference at the Justice Department, Barr said that he did not foresee any criminal investigations involving Obama or Biden, despite Trump’s push. And he went on to decry the kind of politics that leads to such thinly substantiated allegations.

“The legal tactic has been to gin up allegations of criminality by one’s political opponents based on the flimsiest of legal theories,” Barr said. He added that “as long as I’m attorney general, the criminal justice system will not by used for partisan political ends. And this is especially true for the upcoming elections in November.”

Barr went on: “We cannot allow this process to be hijacked by efforts to drum up criminal investigations of either candidate. And I’m committed that this election will be conducted without this kind of interference.”

The comments came in response to a question about Trump’s “Obamagate” allegations, but they could be read as also about Trump and the Russia investigation, which Barr has repeatedly derided in stark terms. Barr made a point to spotlight those allegations in his comments Monday.

“What happened to the president in the 2016 election and throughout the first two years of his administration was abhorrent,” Barr said. “It was a grave injustice, and it was unprecedented in American history.”

Right before those above comments, Barr suggested he was talking more about Trump’s “Obamagate” allegation than anything else. He said he would not comment “on what the president — or Vice President Biden, for that matter — say in connection with their campaigns,” for instance — almost tossing in Biden for good measure as he referred to what Trump has been saying.

His comments also more prominently referenced not what happened in the past, but “the upcoming elections in November.” While Biden has been critical of Trump, the one candidate aggressively pressing the idea of investigating wrongdoing by his opponent right now is Trump.

Trump last week even seemed to suggest the possibility — as he did in 2016 with Hillary Clinton — of criminal wrongdoing by and even prison time for his electoral opponent. He said “people should be going to jail for this stuff,” adding: “This was all Obama; this was all Biden. These people were corrupt.”

It’s significant that Barr is dismissing the idea of any criminal investigation involving Trump’s 2020 opponent — especially given that the FBI actually did investigate Trump’s opponent in 2016. But otherwise, his comments will ring rather hollow to his critics — and with very legitimate reason.

While Barr paints his Justice Department as above politics, he has shown a consistent tendency to make decisions and offer public commentary that aligns with Trump in cases involving the president and his allies. Most prominent on that count is Barr’s misleading summary of Robert S. Mueller III’s special counsel report. But his Justice Department has also recently intervened twice — in extraordinary manner — in favor of two Trump allies facing criminal sentences: Roger Stone and now Michael Flynn.

Barr’s words will also ring somewhat hollow given similarities to the last time he seemingly rebuked Trump. Back in February, Trump derided prosecutors’ sentencing recommendation in the Stone case, right before Barr’s Justice Department reversed course on it. Barr went on to make public pleas for Trump to stop tweeting about and weighing in on such ongoing Justice Department matters, and he reportedly even floated the idea of resigning. He said Trump’s comments “make it impossible for me to do my job.”

Well, Trump didn’t stop his behavior, but Barr seems to have given up pressing the issue. Critics at the time suggested Barr’s plea was just for show, and there’s little to dispute that at this point. Even after Trump continued to weigh in on the Flynn case, for example, Barr’s Justice Department made a decision that aligned with Trump’s wishes.

So there is certainly reason for skepticism about whether Barr is just saying the politically expedient thing. That’s reinforced by how much he has teed up other potential targets (apart from Obama and Biden) in U.S. Attorney John Durham’s probe of the Russia investigation’s origins. Barr also made a point Monday to say that just because certain things don’t rise to a criminal level, that doesn’t mean they aren’t abuses of power — a comment that could be read to allude to high-ranking officials in the Obama administration.

But whatever Barr’s true intentions or motivations, it’s worth noting that Trump’s staunchly aligned attorney general — one who has in the past lent credence himself to some conspiracy theories — just undercut Trump’s latest one. That seems worthy of consideration as Trump and his allies continue to push this.