(NewsNation) — House Republicans are expected to bring a resolution to formalize the impeachment inquiry into President Joe Biden to the floor Wednesday for a full vote.

The House Rules Committee voted on the resolution on 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.

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 on 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 that he will be testifying before Congress in a public setting, but will not appear for the closed-door questioning Republicans have demanded.

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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 will need 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 can only afford to lose three votes.

That means convincing moderate Republicans who have been less than enthusiastic about impeachment investigations and those in swing districts who 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.