WASHINGTON (NEXSTAR) — The top Republican in the U.S. House of Representatives says he will not support a commission to look into the Jan. 6 riot at the U.S. Capitol.

The plan against which House Minority Leader Kevin McCarthy of California is now pushing back has the support of Democrats who now control both chambers of Congress, the White House and some Republicans.

Democrats said they’re moving forward with forming the commission regardless of McCarthy’s objections.

“It really is not understanding of the seriousness and the nature of what happened on Jan. 6,” Rep. Rosa DeLauro, D-Conn., said.

The proposed commission is modeled after the similar body formed to look into the terrorist attacks of Sept. 11, 2001. Made up of five independent Democratic appointees and five independent Republican appointees, it would examine the origins of the Jan. 6 riot and the security breakdown that allowed it.

“This is not a game,” Rep. Jim McGovern, D-Mass., said. “Clearly, we weren’t prepared and we need to be better prepared. That’s what this is all about. This can’t be politics as usual.”

But McCarthy called the commission shortsighted. He argued other groups like Black Lives Matter should be investigated following the at times violent unrest sparked by the death of George Floyd at the hands of Minneapolis police last year.

Senate Minority Leader Mitch McConnell, R-Ky., added that he’s concerned the commission lacks balance and could interfere with other ongoing investigations. While he stopped short of saying he opposed the commission, he said Republicans “need to read the fine print.”

But Rep. John Katko, R-N.Y., who negotiated the commission’s terms for the GOP, has defended its scope and purposes.

“The American people expect Congress to put partisanship aside for the sake of our homeland security,” Katko said during a Tuesday hearing. “That is exactly what this bill does.”

Sen. Dick Durbin, D-Ill., said he’s disappointed that Republicans seem to be trying to sweep the attack under the rug.

“I thought the videotape would speak for itself,” he said. “it was an insurrectionist mob that took human lives and injured innocent people, and I saw it in action.”

He previously opposed the commission but now says both sides should back the effort.

“It’s hard to take Kevin McCarthy seriously at this point,” Rep. Hakeem Jeffries, D-N.Y., said. “I don’t know what Kevin McCarthy is afraid of.”

Jeffries said the House is expected to vote on the proposal Wednesday. Senate Majority Leader Chuck Schumer, also of New York, vowed to bring the plan to a vote on the Senate floor after that and called on Republicans to back the effort.