The Democrats impeachment inquiry into President Donald Trump may just be starting, but it’s already damaged the 2020 ambitions of one high profile political figure—Joe Biden.

When the impeachment frenzy began in September, the former vice president was still leading his Democrat rivals by solid margins, according to national and state polls. Weeks of revelations about influence peddling in the Obama-era State Department and the conflicts of interest between the former vice president’s office and the business interests of his youngest son, Hunter, however, have taken their toll.

This was first evidenced by the Biden campaign’s fundraising troubles and has more recently been exhibited by the former vice president’s slippage in the polls.

Since starting this campaign in late-April, Biden has dropped from leading his fellow 2020 Democrats by as much as double digits in Iowa, New Hampshire, and Nevada. A poll released from Iowa in late-October showed the former vice president in fourth place, trailing not only Sens. Bernie Sanders (I-VT) and Warren (D-MA), but also South Bend Mayor Pete Buttigieg. Since that time, two other polls have also shown Biden firmly in fourth place, according to polling data compiled by Real Clear Politics.

A similar situation has played out in New Hampshire, where Biden once led by more than 15 percentage points, the former vice president has been eclipsed by neighboring state rival, Warren. In fact, Biden had not led Warren in the first primary state in any poll taken between mid-September and November. That trend was only broken on Monday when a Quinnipiac Poll found the former vice president with a four percentage point advantage over Warren in New Hampshire. Although Biden’s campaign was quick to laud the poll as proof their campaign was rebounding, they failed to mention that the former vice president’s lead was exactly within the margin of error.

Biden has also faltered nationally in the race for the Democrat nomination, although to less of a degree. In the weeks after Biden first announced his campaign, he led the field by as much as 32 percentage points. In comparison, a Quinnipiac Poll from October found the former vice president trailing Warren, 21 percent to 28 percent, respectively. A similar Quinnipiac Poll taken just before the most recent Democrat presidential primary, which most pundits agreed was not Biden’s best performance, had seen Warren leading the former vice president more narrowly, 30 percent to 27 percent.

Several national polls from the past week continue to show Biden in decline. A Monmouth University poll conducted between October 30 and November 3, found the former vice president in a statistical tie with Warren, with both Democrats pulling 23 percent of the vote. Likewise, a poll conducted by The Economist and YouGov between November 3 through November 5 showed Biden with narrow one point advantage, well within the margin of error, over Warren.

Not only are Biden’s fortunes dropping in the race for the Democrat nomination, but his viability for the general election is also taking a hit. When Biden first entered the 2020 race, most polls had him leading the president by wide margins. In June, alone, a Quinnipiac Poll had Biden leading Trump in a head-t0-head matchup by 13 percentage points, 53 percent to 40 percent. Now the former vice presidents leads Trump narrowly, often within the margin of error. An Emerson poll conducted in October, indicated Biden only had a one percentage point advantage over Trump, 51 percent to 49 percent, in a hypothetical general election.

The Morning Consult found a similar trend in its national polling data. In between June and October, Trump was able to cut Biden’s lead in a potential general election by half. In June, the Morning Consult’s poll found Biden with an 11 point advantage over the incumbent. The same poll conduct at the end of October found the former vice president only leading Trump by five percentage points. The president’s ability came from improved numbers among women and voters between the ages of 18-to-29 years of age—two demographic groups essential to a Democrat’s retaking the White House in 2020.

Biden’s drop in the polls has occurred as his son’s wheeling and dealing in Ukraine has come to for-front of the impeachment inquiry. The controversy started when Trump suggested the Ukrainian government probe how Hunter Biden secured an appointment to the board of directors of Burisma Holdings, an eastern European oil and gas Ukrainian government probe Hunter Biden’s role with Burisma Holdings. The younger Biden joined the company in 2014 around the same time his father was appointed to oversee Obama administration policy in Ukraine.

As Peter Schweizer, senior contributor at Breitbart News, detailed in his book Secret Empires: How the American Political Class Hides Corruption and Enriches Family and Friends, Hunter Biden secured the position, which paid as much as $83,000 per month, despite having no background in energy or Ukraine.

Adding to concerns is the fact that at the time Hunter Biden joined Burisma, the company was seen as actively courting Western leaders to prevent further scrutiny of its business practices. The same month Hunter Biden was tapped for the group’s board, the government of Great Britain froze accounts belonging to Burisma founder Mykola Zlochevsky under suspicion of money laundering.

Not only had Zlochevsky had his assets frozen in Great Britain, but the former Ukrainian minister of natural resources was also facing suspicions of public corruption at home. Zlochevsky would later be charged with corruption for using his ministerial office to approve oil and gas licenses to companies under his control.

It is in the context of Burisma and Zlochevsky’s legal troubles that Joe Biden’s political influence has raised the most red flags. The former vice president has particularly drawn questions over his conduct in demanding the Ukrainian government fire its top prosecutor, Viktor Shokin, in 2016.

Joe Biden, who has publicly bragged about the firing, reportedly threatened to withhold more than one billion dollars in U.S. aid if the Ukrainian government did not remove Shokin. He has claimed the demand came from then-President Barack Obama, who had allegedly lost faith in the prosecutor’s ability to tackle corruption.

Unofficially, though, it was known that Shokin was investigating both Burisma and Zlochevsky for public corruption. It is uncertain if the probe extended to Hunter Biden, although Shokin has recently admitted that prior to his ouster he was warned to back off the matter.

Regardless of what occurred, Shokin’s successor, who is now himself being investigated for public corruption, dropped the investigation into Burisma and Zlochevsky. Although the former vice president and his son have denied any wrongdoing, voters do not seem to be buying their arguments.

A recent poll by the Associated Press found that 69 percent of Americans believe Hunter Biden’s work on behalf of Burisma was inappropriate. Furthermore, a Harvard/Harris poll taken at the same time showed that a 51 percent of Americans think the younger Biden should return any money he made through his ventures in Ukraine.