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This week's vote entirely along party lines by the Republican-controlled House of Representatives to formally launch an impeachment inquiry into President Biden immediately impacted the president's 2024 re-election campaign.

A fundraising email sent hours later by Vice President Kamala Harris instantly caught fire.

A source familiar with the Biden re-election team's thinking told Fox News that the email was the most lucrative that has been sent so far this month.

"It was the best performing fundraising email the vice president has signed this cycle," the source added.

HOUSE VOTES TO AUTHORIZE BIDEN IMPEACHMENT INQUIRY

President Joe Biden speaks at a campaign rally in June

President Joe Biden speaks at a campaign rally at the Mayflower Hotel on June 23, 2023 in Washington, DC. (Chip Somodevilla/Getty Images)

The impeachment vote formalized an inquiry that began in September to investigate whether the president financially benefited from some of his family's business dealings.

POLL: SUPPORT FOR BIDEN IMPEACHMENT INQUIRY GROWS

Three Republican-led House committees are looking into connections between the president and his son Hunter Biden's business dealings from 2014-2017, during the elder Biden's final three years as vice president, and after he left office.

Hunter Biden reiterated this week that his father was not involved in his dealings as a board member of Ukrainian energy company Burisma, or in his partnership with a Chinese private businessman.  

Hunter Biden on Capitol Hill

Hunter Biden, son of President Joe Biden, talks to reporters at the U.S. Capitol, in Washington, Wednesday, Dec. 13, 2023. Hunter Biden lashed out at Republican investigators who have been digging into his business dealings, insisting outside the Capitol he will only testify before a congressional committee in public.  (AP Photo/Jose Luis Magana)

Republican investigators have so far not found any solid evidence that Biden personally benefited, but they argue there's more to uncover.

While the vote to formalize the inquiry is apparently boosting Biden's 2024 re-election fundraising, it may also pay dividends in other ways.

It could energize the base of a party that polls suggest is anything but energized by the president's re-election drive. 

The Biden campaign launched a blistering broadside against House Republicans early this week, ahead of Wednesday's vote, accusing them of doing the bidding of Biden's likely GOP challenger next November - former President Donald Trump, the commanding front-runner for the 2024 Republican nomination.

"The only, single fact in this entire sham impeachment exercise is that it’s a nakedly transparent ploy by House MAGA Republicans to boost Donald Trump’s presidential campaign," Biden campaign communications director Michael Tyler charged in a memo.

Trump at rally

Former President Donald Trump leaves the stage at a campaign rally Saturday, Nov. 11, 2023, in Claremont, N.H. (AP Photo/Reba Saldanha)

The memo spotlights a quote that went viral from Republican Rep. Troy Nehls of Texas, who said the impeachment inquiry would give the former president "a little bit of ammo to fire back."

But the impeachment inquiry also provides plenty of downsides for Biden's re-election effort. 

Republicans for years have viewed Hunter Biden's controversies as a political liability for his father. And now, a formal impeachment investigation - with public hearings - could give the Biden campaign lots of headaches.

"It keeps the negative story about his family in the news," longtime Republican strategist and communicator Ryan Williams told Fox News. "The impeachment inquiry highlights potential wrongdoing on the part of the president’s son and brother and tries to link it directly to him."

Republicans can also leverage the impeachment proceedings - as well as Hunter Biden's legal cases - to deflect attention away from Trump's extremely serious court cases.

Trump made history earlier this year as the first former or current president to be indicted for a crime, but his four indictments — including in federal court in Washington, D.C., and in Fulton County court in Georgia — on charges he tried to overturn his 2020 presidential election loss.

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"It tries to distract from the serious legal issues Trump is facing and basically at the end of the day," said Ryan, a veteran of multiple GOP presidential campaigns.

He emphasized that inquiry "shows voters both candidates are facing investigations. It muddies the waters. It tries to make things murky even though the criminal trials that President Trump is facing are much different than the Republican-led inquiry in the House."

Biden primary challenger Rep. Dean Phillips predicts he will ‘surprise’ people with his show in next month’s New Hampshire primary

Democratic Rep. Dean Phillips of Minnesota, who is primary challenging President Biden, speaks with voters in Portsmouth, New Hampshire, on Dec. 3, 2023 (Fox News - Paul Steinhauser)

Rep. Dean Phillips of Minnesota, who's running a long-shot Democratic primary challenge against the president, made a similar argument.

"I don’t see the evidence of it, but yes, when your own son and your own brother are clearly, at the very least unethical and at worst, doing illegal things — my goodness, of course the country pays attention to it," Phillips said in an interview with the news website Semafor. "People do believe that it perhaps makes him unelectable — somehow, it conflates him with the Trump family’s indiscretions." 

But Democratic strategist Chris Moyer, who served on a handful of presidential campaigns, disagreed.

"No one is Donald Trump when it comes to corruption, breaking the law, and violating his oath of office," he argued, when asked if the inquiry lessens the sting of Trump’s own legal controversies.

Biden became the second straight president to face an impeachment inquiry as his re-election was underway, following Trump.

Veteran political scientist Wayne Lesperance spotlighted that "perhaps the biggest casualty of the recent vote is the impeachment process itself. Long gone are the days when impeachment was a last resort for members of Congress who have exhausted all other options of holding the President accountable."

Lesperance, the president of New Hampshire-based New England College, said that "the frequency with which impeachment has occurred in recent years has reduced the process to yet another partisan tool for whichever party is in power. The real loser in these processes has become the American people, who continue to lose faith in their beleaguered system of government."

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