Why do Kevin McCarthy's Republicans want to impeach Joe Biden now?

Speaker of the House Kevin McCarthy has announced a formal impeachment inquiry into President Joe Biden.

After weeks of hints and veiled suggestions, the California Republican took the plunge in a brief statement to the press that there were "serious and credible allegations into President Biden's conduct" that "taken together" necessitated further investigation.

Impeachment by the House of Representatives is the first step in a formal process to remove a president - or other senior executive or judicial official - from office. It requires a simple majority vote in the chamber to trigger a trial in the US Senate, where a two-thirds majority is necessary for conviction and removal.

President Donald Trump was impeached twice when Democrats controlled the House - over Ukraine in 2019 and the January 6 Capitol riot in 2021 - but was acquitted by the Senate on both occasions.

In his announcement to reporters at the US Capitol, Mr McCarthy ticked through a series of accusations against the president and the president's son, Hunter Biden.

He accused the president of lying about knowledge of his son's business dealings and said that "Biden family members" had received millions of dollars in payments from shell companies and that transactions had been flagged as questionable by the US Treasury Department. He noted that an FBI informant had passed along an allegation that Mr Biden had taken a bribe in exchange for official actions as vice-president, and that he had used his government office to coordinate with his son's business partners.

Mr McCarthy also alleged that the Biden administration had given the president's family and associates special treatment during its investigations into possible criminal violations.

Republicans have not found concrete evidence of misconduct by the president, however.

The speaker's action came approximately two months after a House committee heard testimony from two Internal Revenue Service officials who claimed Mr Biden's Justice Department prevented a more thorough investigation of the president's involvement in Hunter Biden's personal finances.

In late July, Republican Senator Chuck Grassley released a Federal Bureau of Investigation document detailing how a trusted intelligence source had passed along allegations that the Biden family had received two $5 million payments from a Ukrainian energy company after then Vice-President Biden pressured Ukraine to remove a senior government official in charge of investigating corruption.

Neither the IRS investigators nor the FBI document provided conclusive evidence of illegal or improper conduct by the president, but Republicans in the House asserted that the information was enough to trigger a formal impeachment inquiry.

Mr McCarthy said that impeachment proceedings would give House Republicans "the full power to gather all the facts and answers for the American public". Courts have traditionally given congressional committees more sweeping authority to issue and enforce subpoenas for documents and testimony when those orders are issued as part of an impeachment inquiry.

In July, Mr McCarthy drew parallels with the administration of Richard Nixon, who was the target of a congressional inquiry in 1974 but resigned before he was formally impeached.

"We're watching this administration use government much like Richard Nixon by denying us to get the information that we need," he said.

In the past, the House speaker had been reluctant to endorse calls from some Republicans in his chamber to initiate impeachment proceedings, saying that it was too soon to follow that course of action. He was under increasing pressure from right-wing members of his party to move more quickly, however. And with only a narrow Republican majority in the House of Representatives and tough votes on government spending looming in the coming weeks, Mr McCarthy changed course.

But even that many not be enough to satisfy the speaker's conservative critics. Shortly after Mr McCarthy's impeachment announcement, Congressman Matt Gaetz of Florida took to the floor of the House of Representatives to express his disappointment.

"This is a baby step following weeks of pressure from House conservatives to do more," he said. "We must move faster."

The ultimate success of an impeachment resolution in the House is very much in doubt. Republicans hold a narrow majority in the chamber and some centrists in the party, contemplating challenging re-election races in November 2024, have expressed unease with moving forward with a process that will only enflame political divisions in America.

The Biden team was quick to push back against Mr McCarthy's impeachment announcement.

"House Republicans have been investigating the President for nine months, and they've turned up no evidence of wrongdoing," White House spokesperson Ian Sams wrote in a social media post.

Only three US presidents have been impeached - Andrew Johnson in 1868, Bill Clinton in 1998 and Donald Trump twice. None was convicted by the Senate.

Democrats currently have a 51-49 majority in the Senate, virtually ensuring that any Biden impeachment referral from the House will meet a similar fate.