One might think that the last thing a candidate vying to lead the Democratic Party would want to do is revive the divisions that pitted supporters of Hillary Clinton and Bernie Sanders against each other during the 2016 presidential primary.

And yet that is exactly what Tom Perez, one of the leading contenders for chair of the Democratic National Committee, did on Wednesday. Perez, Obama’s former labor secretary, endorsed Sanders’s supporters long-standing claim that the primary was “rigged” against the Vermont senator — a line Clinton backers have long derided as a deluded conspiracy theory.

"We heard loudly and clearly yesterday from Bernie supporters that the process was rigged, and it was. And you've got to be honest about it," Perez told a group of Democratic lawmakers in Kansas, according to a report by MSNBC’s Alex Seitz-Wald.

By late Wednesday night, Perez was furiously backing off the comments. On Twitter, he said that he had “misspoke” and clarified that Clinton had won “fair and square” — but that it was essential for the next DNC chair to be transparent to avoid the perception that “a thumb was placed on the scale.”

I have been asked by friends about a quote and want to be clear about what I said and that I misspoke. — Tom Perez (@TomPerez) February 9, 2017

Hillary became our nominee fair and square, and she won more votes in the primary—and general—than her opponents. — Tom Perez (@TomPerez) February 9, 2017

As I've said repeatedly, we can't have a primary process where it is even perceived that a thumb was on the scale. — Tom Perez (@TomPerez) February 9, 2017

The next DNC chair must be transparent and objective for Democrats to be engaged. — Tom Perez (@TomPerez) February 9, 2017

Perez, it’s worth noting, is generally seen as having the Obama and Clinton wings of the party behind him. But his leading opponent for the position, Rep. Keith Ellison (D-MN), endorsed Sanders during the primary and has the strong backing of both the Vermont senator and Sanders allies in the media. (The third leading choice, Mayor Pete Buttigieg of South Bend, Indiana, has pitched himself as a consensus candidate to prevent the race from becoming a referendum on the primary.)

This dynamic has put Perez in the position of needing to say things that sound appealing and nonthreatening to the Sanders wing of the party, and Ellison in the position of needing to say things that sound appealing and nonthreatening to the Clinton wing of the party. The risk of going too hard after the other side, as Perez demonstrated, is that it can undermine certain “friend”-ships — and force you to clarify where you stand.