Sen. Josh Hawley, R-Mo., on Wednesday became the first Republican senator to publicly say he will object to the certification of the presidential election results when a joint session of Congress meets in one week to formally certify President-elect Joe Biden‘s 306-232 Electoral College victory over President Trump.

Roughly a dozen Trump supporters in the House – led by Rep. Mo Brooks of Alabama – have said they will challenge the slate of electors from six battleground states where Biden narrowly edged Trump in last month’s election. But the challenge of at least one senator is needed for both houses of Congress to debate the objections.

Hawley, a conservative lawmaker and Trump supporter, said in a release issued Wednesday that in his objection he’ll highlight what he said was the failure of some states – most notably Pennsylvania – to follow their own election laws. A number of states – including Pennsylvania – allowed for a greater use of absentee balloting due to serious health concerns over in-person voting at polling stations amid the coronavirus pandemic.

“I cannot vote to certify the electoral college results on January 6 without raising the fact that some states, particularly Pennsylvania, failed to follow their own state election laws,” the senator highlighted in a statement.

Hawley also charged, “I cannot vote to certify without pointing out the unprecedented effort of mega corporations, including Facebook and Twitter, to interfere in this election, in support of Joe Biden. At the very least, Congress should investigate allegations of voter fraud and adopt measures to secure the integrity of our elections. But Congress has so far failed to act.”

He pointed out that “following both the 2004 and 2016 elections, Democrats in Congress objected during the certification of electoral votes in order to raise concerns about election integrity. They were praised by Democratic leadership and the media when they did. And they were entitled to do so. But now those of us concerned about the integrity of this election are entitled to do the same.”

Trump met at the White House last week for a strategy session with some of the House Republicans who have said they will object to the election certification.

Senate GOP leaders are against this effort to challenge Biden’s win, with Senate Majority Leader Mitch McConnell recognizing the former vice president’s victory, and behind closed doors urging Senate Republicans not to contest the election results.

But with Hawley joining the small group of House Republicans in objecting, the joint session of Congress on Jan. 6 would be dissolved and the House and Senate would then meet separately for two hours to debate a contested state’s electoral vote.

Each body would then vote whether to accept or reject that state’s slate of electoral votes. Then the House and Senate reconvene in the joint session. The last time this happened (and only the second time in U.S. history) was in January 2005, following President’ George W. Bush’s narrow reelection victory over Democratic challenger Sen. John Kerry of Massachusetts. One Senate Democrat – Sen. Barbara Boxer of California – and one House Democrat – Rep. Stephanie Tubbs Jones – objected. In 2017, a handful of House Democrats objected to Trump’s victory over Democratic nominee Hillary Clinton, but no Senate Democrats joined them.

A state’s slate of electoral votes would only tossed if both the House and Senate vote to do so.

But with the Democrats controlling the House and most Senate Republicans not expected to back the push to contest the results, it’s extremely unlikely there would be enough votes to reject any state’s certification.

While Hawley is the first GOP senator to say he’d object to the certification, Senator-elect Tommy Tuberville of Alabama, Sen. Kelly Loeffler of Georgia, and Sen. Ted Cruz of Texas could potentially join their colleague from Missouri.