President Joe Biden and House Speaker Mike Johnson.

House Republicans voted Wednesday to formalize an impeachment inquiry into President Joe Biden as their investigation reaches a critical juncture and right-wing pressure grows.

In a 221-212 vote, all GOP members supported the resolution to formalize the inquiry – including Rep. Ken Buck of Colorado, who had said earlier this week he was leaning against it.

Up until this point, House Republicans had not had enough votes to legitimize their ongoing inquiry with a full chamber vote. The probe has struggled to uncover wrongdoing by the president, which is why it hadn’t garnered the unified support of the full GOP conference.

Part of the reason for Wednesday’s vote came from the White House telling the trio of GOP-led congressional committees leading the investigation that its subpoenas were illegitimate without a formal House vote to authorize the inquiry. That prompted some reluctant, more moderate Republican lawmakers to get on board with their party’s investigative efforts. The Trump administration made a similar argument against House Democrats at the start of his 2019 impeachment.

House Oversight Chairman James Comer and Judiciary Chairman Jim Jordan took a victory lap after Wednesday’s vote, overcoming the lack of support for the inquiry when it was first unilaterally launched in September under then-Speaker Kevin McCarthy.

“We are very pleased with the vote today,” Comer, a Kentucky Republican, told reporters. “I think that sent a message loud and clear to the White House.”

Jordan said the vote would “help us get those key individuals in to speak to us in a more timely fashion.”

“The House has now spoken and I think pretty loudly, pretty clearly with every single Republican voting in favor of moving into this official impeachment inquiry phase,” Jordan said.

Biden said in a statement shortly after the vote, “Instead of doing anything to help make Americans’ lives better, they are focused on attacking me with lies. Instead of doing their job on the urgent work that needs to be done, they are choosing to waste time on this baseless political stunt that even Republicans in Congress admit is not supported by facts.”

The vote came after Hunter Biden defied Republican investigators’ subpoena for closed-door testimony and reiterated that he is willing to testify publicly as part of the GOP-led investigation into the president.

“I am here to testify at a public hearing, today, to answer any of the committees’ legitimate questions,” Hunter Biden said in his first public statement since being criminally indicted twice. “Republicans do not want an open process where Americans can see their tactics, expose their baseless inquiry, or hear what I have to say.”

Following Hunter’s statement, the Republican chairman behind the impeachment inquiry into the president said they will start contempt of Congress proceedings against the president’s son for not participating in the closed-door deposition.

Hunter defended his father, saying, “Let me state as clearly as I can, my father was not financially involved in my business, not as a practicing lawyer, not as a board member of Burisma, not in my partnership with the Chinese private businessman, not in my investments home nor abroad, and certainly not as an artist.”

He continued, “In the depths of my addiction, I was extremely irresponsible with my finances. But to suggest that is grounds for an impeachment inquiry is beyond the absurd. It’s shameless. There is no evidence to support the allegations that my father was financially involved in my business because it did not happen.”

The argument from Republican proponents of the effort, according to multiple GOP lawmakers and aides, is that a floor vote will strengthen their legal standing against the White House and fortify their subpoenas to secure key witness testimony.

“The inquiry will help us be more informed,” GOP Rep. Nick LaLota, who represents a swing district in New York, told CNN.

Potentially bolstering the GOP inquiry: Last week’s tax indictment against Hunter Biden, which overlapped with many of the alleged financial imports and overseas business deals that Republicans have intensely scrutinized with their own probes.

In response to allegations they have stonewalled the inquiry, a recent White House memo touted that Republicans have accessed more than 35,000 pages of private financial records, more than 2,000 pages of Treasury Department financial reports, at least 36 hours of witness interviews, and just this week began receiving 62,000 more pages from the National Archives including much of Joe Biden’s communications as vice president.

But even as the majority of House Republicans rally around the inquiry vote, GOP leadership has made a point to indicate that formalizing the inquiry does not mean impeaching the president is inevitable, even as pressure within the party and among the Republican base grows.

“We’re not going to prejudge the outcome of this because we can’t,” House Speaker Mike Johnson told reporters earlier this week. “It’s not a political calculation. We’re following the law and we are the rule of law team and I’m going to hold to that.”

House Majority Whip Tom Emmer, a Minnesota Republican, echoed Johnson’s sentiment by telling reporters, “Voting in favor of an impeachment inquiry does not equal impeachment.”

GOP Rep. Matt Gaetz of Florida, who has been pushing Republicans to impeach the president, told CNN the reason he sees his party’s leaders signaling caution is because House Republicans do not have the votes to actually impeach the president, particularly in their shrinking, narrow majority.

“I think it’s a realistic approach,” Gaetz said. “I don’t think we have the votes to impeach anyone.”

Indeed, moderate GOP Rep. Don Bacon of Nebraska, who supports authorizing an impeachment inquiry, said that “more likely than not,” Republicans will not end up bringing articles of impeachment against the president because the evidence will not raise to the bar of high crimes and misdemeanors, the standard for impeachment.

While Republican leaders are emphasizing caution, others in the party are ready to go full steam ahead.

“I think we start the inquiry and I wouldn’t be surprised if the next thing is impeachment,” GOP Rep. Tony Gonzales of Texas told CNN.

At every stage, House Democrats and the White House have refuted and sometimes even debunked the accusations leveled by Republicans, who have tried to connect Joe Biden to his son’s million-dollar overseas deals.

Rep. Jamie Raskin of Maryland, the top Democrat on the House Oversight Committee, attacked Republican efforts to open an impeachment inquiry, and argued that House Republicans are trying to create a “dark cloud” that will follow the president into the election next year.

“That of course is the whole purpose of the impeachment inquiry,” he said Monday. “There is not one particle linking Joe Biden to a crime, and yet they insist that there is going to be a Senate trial for impeachment of Joe Biden in the fall during the presidential campaign,” Raskin said.

Since McCarthy launched the inquiry in September, the trio of committees leading the investigation have interviewed various officials from the Justice Department and Internal Revenue Service while also obtaining a mountain of documents and new bank records, including from Biden family members.

Even as Republicans issue new subpoenas and schedule more depositions, including with the president’s brother and son, they still have not uncovered credible evidence that backs up their loftiest claims against Biden. There has only been one hearing related to the inquiry since its launch, where the expert witnesses called by Republicans acknowledged GOP investigators hadn’t yet presented enough evidence to prove the accusations they were leveling.

In the lead-up to Wednesday’s vote, each of the three committees, leading a different portion of the inquiry had sought to build momentum.

This story and headline have been updated with additional reporting.

CNN’s Haley Talbot and Samantha Waldenberg contributed to this report.