Why the Ukraine scandal presents danger and opportunity for Joe Biden's White House bid

For a candidate with a long history in politics, former U.S. vice-president Joe Biden hadplenty on his record that could come back to haunt him in his run for the 2020 Democratic presidential nomination, but few likely would have guessed that a seemingly innocuous episode involving Ukraine would threaten to consume his campaign.

Biden's involvement as the point man for the Obama administration in rooting out corruption in Ukraine late in their second term has become the focus of attacks by U.S. President Donald Trump, who views Biden as the most likely contender to emerge from a crowded field of Democrats looking to challenge him in the race for the White House.

Trump's determination to twist and spin Biden's history in Ukraine, and ensnare Biden's son, Hunter, along the way, has put the president at risk ofimpeachment for asking Ukrainian President Volodymyr Zelensky to launch an investigation into Biden.

Some political strategists say the attacks represent a double-edged sword for Biden that could either hurt or helphis campaign.

While the former vice-president and his son have not been shown to have done anything illegal, Trump and his allies have slung plenty of mud their way and some of it could stick.

But targeting Biden this way could also elevate his candidacy by signalling to Democrats that he's the potential competitor Trump fears the most heading into the 2020 campaign.

The Ukraine story explained

The main accusation, which is now the subject ofpolitical ads from the Trump campaign,is that Hunter Biden traded on his father's name for financial gain, and that the former vice-president used his political influence to interfere in Ukraine's affairs and protect his son.

In 2014, Hunter Biden was appointed to the board of BurismaHoldings, a Ukrainian energy company.He was reportedly paid $50,000 a month to work in an industry in which he had no previous experience. The company's founder, Mykola Zlochevsky, was the country's former ecology minister and had been under investigation for allegedly embezzling millions in public funds.

Anti-corruption groups in Ukraine note it is common for foreigners to sit on company boards there, to offer an air of legitimacy.

In 2016, in his role as vice-president, Joe Biden led the charge to oust Ukraine's prosecutor general,Viktor Shokin, for not doing enough to root out corruption. Shokin'sfiring is the eventTrump has seized on, arguing that it shows Bidenpressured a foreign country into firing its top prosecutor and drop an investigation into corrupt business practices at a company involving Biden's son.

The reality, however, is much different. Biden was part of an international effort to pressure Ukraine to deal with corruption, and Burisma was not under investigation at the time Shokin was fired.

"Basically, civil society all were calling to dismiss Shokin because of his ineffectiveness and sabotage in the investigation and prosecution of the oligarchs, including ZlochevskyandBurisma," said Anastasiya Kozlovtseva of Transparency International Ukraine, a not-for-profitanti-corruption watchdog in Kiev.

In Ukraine, Shokin's dismissal "was not connected to the name of Biden at all," Kozlovtseva said, noting the European Union and International Monetary Fund were among those clamouring for change.

Pushing out an ineffectiveprosecutor would have brought more attention to Burisma, not less, she points out, contrary to Trump's accusations.

Those facts didn't stop Trump's campaign from pursuing Ukraine as a line of attack. In May, a story appeared in the New York Timesthat laidout Trump's case, only making passing mention of Trump's own efforts to persuade Ukraine to investigateBiden.

At that time, Ukrainian Prosecutor General Yuriy Lutsenko said there was no evidence of wrongdoing by either Joe or Hunter Bidenin 2016. That was repeated on Friday by Lutsenko's successor,Ruslan Ryaboshapka. He didannounce a review of high-profile cases involving associates of former president Viktor Yanukovych, cases which include some related to Burisma.

Campaign consequences

While Trump's corruption allegations against Biden aren't supported by evidence, the lingering cloud of controversy kicked up by the president could have consequences, both good and bad, for Biden's presidential ambitions.

Democratic strategist Jim Manley doesn't see the attacks having a long-term impact on Democratic primary voters. He dismissesTrump's broadsides as "cheap smash-mouth politics."

"I don't think this is resonating very much with Democrats;it's just serving as more red meat to the Republican base," he said.

But Democratic political consultant Mike Mikussays even though the accusation doesn't stand up to scrutiny, it can still give voters considering Biden pause.

He draws a parallel between Biden's situation and the concern around Hillary Clinton's use of a private email server as secretary of state that cast a cloud over her campaign for president in 2016 and remains a key Republican talking point to this day.

If it doesn't plant a seed of doubt in voters' minds, it is at the very least a distraction, Mikus says, notingthe issue is dominating reporters' questions on the campaign trail.

"They're not asking him about his health-care plan. They're not asking him about his jobs plan. They're asking him about this and that's a problem."

Though the Ukraine affair could be a weak spot for Biden, don't expect his Democratic opponents to exploit it, says Ian Russell, former national political director for the Democratic Congressional Campaign Committee.

"Democrat on Democrat violence is not something that Democratic primary voters are into right now," he said.

He points out that attacks on Biden fromKamala Harris and Julian Castro during debates ultimately didn't prove successful.

That means Biden's opponents are likely to steer clear of Hunter Biden's past, including his work in China, which Trump has also seized on as a line of attack.

"In a lot of ways, it disarms his opponents in the primary," said Mikus, the Pittsburgh-based strategist. "Now, there's a built-in defencewhere, if they bring it up, it can easily be deflected as, 'They're just repeating a debunked attack by Donald Trump."

How does Biden respond?

The strategists say how this all plays out politically for Biden will be determined largely by how he responds. Biden has long sought to make his campaign a one-on-one fight with Trump, at the expense of his Democratic primaryopponents.

"Now let me make something clear to Mr. Trump and his hatchetmen and the special interests funding his attacks against me:I'm not going anywhere," Biden said at a campaign stop in Reno, Nev.,this week.

"You are not going to destroy me and you're not going to destroy my family."

Democratic competitorElizabeth Warren has chipped away at Biden's lead in the polls, and she and Bernie Sanders surpassed Biden in the latestfundraisingfigures.

Russell says those developments aren't the result oftheUkraine story, but rather the influence ofprogressive voters who are less concerned about electability and more concerned about which candidate can deliver the kind oflong-term structural change they want to address issues like health care and income inequality.

For voters whose primary concern is determining which candidateis best suited to beat Trump, the president'sfocus on Biden could help. Reminding them, Mikus says, that the attacks mean Trump sees Biden as his biggest threat.

"They can remind voters that Donald Trump is more or less committing crimes to destroy Joe Biden because he's so afraid of facing Joe Biden in a general election," Mikus said, noting Biden polls well against Trump in key battleground states like Pennsylvania, Michigan andWisconsin.

In a list of national polls compiled by Real Clear Politics, Biden beats Trump in a head-to-head matchup in all but one.

Mikus suggests Biden should go hard at Trump.

"When there's a bully, sometimes you have to hit them in the nose."

Manley says there's a delicate balance between giving the attacks more oxygen and fighting back.

Many operatives from Hillary Clinton's presidential campaign felt they didn't respond strongly enough to Trump's attacks in 2016, he says.

"I don't envy [Biden], but if you learn one thing from the Clinton campaign, it'sthat you can't let things go unanswered."

How this ultimately plays out with voters may not reveal itself for a while yet. Mikus says thesetypes of political battlesusually take a few weeks to register in the polls.

"The swing voters, who are a little less dialed-in to the day-to-day battles, it's going to take a while for this to sink in and I think it's still up for grabs as to how they respond.

Manley says Biden still has a lot of work ahead.

"He still has to show Democrats that he's best positioned to take on Trump he hasn't sealed the deal yet."