For months, many Republicans called for a special counsel to investigate Hunter Biden. But now that the Department of Justice has designated U.S. Attorney David Weiss of Delaware to the role, several conservatives are complaining about the appointment.

Attorney General Merrick Garland announced Friday that he appointed Weiss as special counsel in the investigation into Hunter Biden's tax case, a move that appeared to be an attempt to insulate the DOJ from Republican criticisms that the process had been politicized. Weiss, a Trump appointee, began the investigation of the president's son in 2018 and has continued to lead the prosecution during the Biden administration.

In 2022, a long list of House and Senate Republicans issued letters calling on the Justice Department to designate a special counsel.

"We believe that in the case of Hunter Biden a Special Counsel must be appointed to preserve the integrity of this investigation and any subsequent prosecution. A Special Counsel would also ensure there is no bias in the investigation or undue influence from the White House," states an April 2022 letter to Garland signed by dozens of House Republicans.

And that September, more than 30 Senate Republicans sent a letter to Garland requesting he designate Weiss as a special counsel in the investigation.

"Given the politicization of the DOJ under your watch and the importance of avoiding any appearance of impropriety, the undersigned request that you provide U.S. Attorney Weiss the full protections and authorities of a special counsel," the senators' letter says. "This is one important action that you can take that will go a long way in restoring faith in our governmental institutions."

But a year later, many of the same politicians contend that a recent plea deal that fell apart changes the circumstances.

Last month, the judge in the case questioned aspects of the deal, including what immunity from future charges the agreement afforded the younger Biden. She asked both sides to continue discussing a plea agreement and return to her with a new proposal. On Friday, plea negotiations with Biden's attorneys over the matter fell apart.

"Mr. Weiss has been compromised. His whole team to me has been compromised. The sweetheart plea deal was written for Hunter Biden in a way that no American would get advantage of that deal," Sen. Lindsey O. Graham of South Carolina, who signed onto the 2022 letter with other Senate Republicans, said on Fox News on Friday. Another signatory, Sen. Charles E. Grassley of Iowa, tweeted on Friday that Weiss "pulled punches/didn't investigate as he shouldve."

House Republicans are accusing Garland of trying to thwart congressional investigations into the Biden family and say that Weiss isn't the right person to serve as special counsel.

"David Weiss can't be trusted and this is just a new way to whitewash the Biden family's corruption. Weiss has already signed off on a sweetheart plea deal that was so awful and unfair that a federal judge rejected it," Russell Dye, a spokesperson for House Judiciary Committee Chairman Jim Jordan, R-Ohio, said in a statement.

Rep. Greg Murphy of North Carolina, one of the signatories to House Republicans' letter, tweeted, "Weiss has already destroyed the credibility of the investigation into Hunter Biden and now he's being elevated to Special Counsel. What could go wrong?"

While Democrats have tried to talk about Hunter Biden as little as possible, Republicans have seized on using the investigations into misconduct by the president's son as political ammunition. Although Republicans have not presented evidence that the president was involved in any wrongdoing, discussions about the case are likely to escalate as the 2024 race ramps up and the legal case continues.

Most Republican presidential candidates have remained skeptical, at best, over whether Weiss's appointment will lead to what they say is an appropriate form of accountability for the president's son.

Sen. Tim Scott of South Carolina, one of the signatories on the 2022 letter to Garland asking for Weiss to be special counsel, now says Weiss's appointment "raises further questions about the independence of Biden's DOJ."

Entrepreneur and GOP presidential candidate Vivek Ramaswamy referenced his previous call to appoint a special counsel, tweeting on Friday, "It happened. Good. Now let's see if it's more than a fig leaf."

Former Vice President Mike Pence was the only GOP candidate who seemed to plainly welcome the move.

"I think it's about time that we saw the appointment of a special counsel to get to the bottom of not only what Hunter Biden was doing but what the Biden family was doing," Pence said on the campaign trail in Iowa. "The American people deserve answers and I welcome the appointment."

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The Washington Post's Hannah Knowles, Marianne LeVine, Perry Stein and David Nakamura contributed to this report.