(NewsNation) — House Republicans on Wednesday voted to formalize the impeachment inquiry into President Joe Biden.

The House Rules Committee first voted on the resolution Tuesday, with the measure passing along party lines following debate over standards for impeachment and the credibility of evidence gathered by the committee so far.

The resolution was approved Wednesday by the full House in a 221-212 party-line vote.

A vote for an inquiry is not the same as a vote for impeachment but does create a formal investigation. Republicans say a formal impeachment inquiry will give them more power to enforce subpoenas and obtain information to conduct the investigation.

In the committee meeting Tuesday, Republicans pointed to Hunter Biden’s refusal to testify in a closed-door deposition as demanded by the House Oversight Committee as justification for a formal inquiry.

The president’s son confirmed Wednesday morning he would testify before Congress in a public setting but will not appear for the closed-door questioning Republicans have demanded.

House Oversight Chair James Comer, R-Ky., has threatened to hold Hunter Biden in contempt if he fails to appear before the committee.

In order to authorize the inquiry, Republicans needed the votes of nearly all of those in the House. With the expulsion of former Rep. George Santos, the party holds a narrow majority of 221-213 seats and could only afford to lose three votes.

The party lost none.

“Today’s unanimous vote by our conference showed that we are united as a conference,” Comer said after the vote.

Some moderate Republicans have been less than enthusiastic about impeachment investigations, and those in swing districts are aware that public support does not favor an impeachment inquiry. Support among critical independent voters has dropped in recent polling.

The move to formalize an inquiry comes after House Republicans have launched multiple investigations into the Biden family and their businesses. Hunter Biden, who is facing multiple indictments on tax-related charges and charges related to illegal possession of a firearm, has been at the center of the investigations.

For impeachment to succeed, however, Republicans will need to provide evidence showing the president was directly involved in his son’s business dealings and used his position to influence policy favorably. So far, they have failed to do so.

The White House called the impeachment inquiry a “baseless” stunt.

“There is a lot of work to be done. But after wasting weeks trying to find a new Speaker of the House and having to expel their own members, Republicans in Congress are leaving for a month without doing anything to address these pressing challenges,” the president said in a statement. “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.”